Indeed, at an informal level, you should subtract/remove from C all its parts that 

        - do belong to B, i.e. h and i;
    and 
        - do not belong to A, i.e. j.

So, what remains of C is g.  At the informal level, at this point the solution is complete.


At a formal level, there are several errors in the Edwin's post.


First, objects/subsets "a", "b", "c" should not present in the lists, because THERE ARE NOT such subsets;
there are A, B and C, but we should not list them, since they are replaced by smaller subsets.


Second, this line in the Edwin's post is incorrect

    (e,f,h,i) U (a,b,c,f,i,j,k) means all of those regions, (a,b,c,e,f,h,i,k).


The correct form for this line is 

    (e,f,h,i) U (f,i,j,k) means all of those regions, (e,f,h,i,j,k).


In this line, "j" was missed by Edwin, which led him to wrong answer later.

Thanks to Ikleyn for correcting my error with region j. I must go back to my
desktop computer. I cannot see everything on the screen here, and when I go back
and forth I make mistakes. I'll start from scratch and try not to make any
mistakes this time.  I'll delete my previous post with the error.

We draw a Venn diagram with three sets.  Label the 8 regions d thru k.
 



C-(B U A') 

A = regions labeled (d,e,g,h)
B = regions labeled (e,f,h,i)
C = regions labeled (g,h,i,j)

Substitute:

(g,h,i,j)-((e,f,h,i) U (d,e,g,h)')

(d,e,g,h)' means (a,b,c,f,i,j,k), that is, everything but (d,e,g,h)

Substitute:

(g,h,i,j)-((e,f,h,i) U (a,b,c,f,i,j,k))

(e,f,h,i) U (a,b,c,f,i,j,k) means all of those regions, (a,b,c,e,f,h,i,j,k)

Substitute:

(g,h,i,j)-(a,b,c,e,f,h,i,j,k)

That means to remove any of these regions (a,b,c,e,f,h,i,k) from (g,h,i,j)
that happen to be part of (g,h,i,j).

So we remove h, i, and j and that leaves (g).

So shade only the region g in the Venn diagram.

So that region is the answer.  It's correct now.

Edwin

Ikleyn sees Venn diagrams as useless.  Here is what AI says about them.

AI:

Venn diagrams are a useful tool for visualizing relationships and identifying
commonalities and differences between different sets of data or concepts. They
offer several advantages:

Visual Representation: Venn diagrams provide a clear and intuitive visual
representation of data, making it easier to understand complex relationships and
comparisons. The diagram's overlapping circles or shapes allow for a quick and
easy grasp of common elements and distinctions.

Set Relationships: Venn diagrams are particularly effective in illustrating the
relationships between different sets of data or concepts. They can show the
intersection (elements that belong to multiple sets), the union (all elements in
all sets), and the complement (elements that belong to one set but not others).

Logical Reasoning: Venn diagrams can aid in logical reasoning and 
problem-solving. They help identify logical relationships, analyze data, and
draw conclusions. By visually organizing information, Venn diagrams can
facilitate the identification of patterns, overlaps, or gaps in the data.

Clarity and Simplicity: Venn diagrams simplify complex information by breaking
it down into manageable parts. They present data in a concise and structured
manner, reducing clutter and enhancing clarity. This clarity makes Venn diagrams
accessible to a wide range of audiences, including those without specialized
knowledge.

Comparative Analysis: Venn diagrams allow for easy comparison of multiple sets
or categories. By visually representing similarities and differences, they help
identify shared characteristics and unique attributes across various groups.
This feature is particularly useful in fields such as statistics, data analysis,
and market research.

Communication and Collaboration: Venn diagrams serve as a common visual language
that facilitates communication and collaboration among individuals or teams.
They can be used to present ideas, discuss concepts, and reach a shared
understanding. Venn diagrams encourage participation and engagement, making them
effective in group settings.

Overall, Venn diagrams offer a powerful and versatile tool for organizing,
analyzing, and communicating information. They enable visual thinkers to grasp
complex relationships easily and provide a structured framework for logical
reasoning and problem-solving.

[If you like AI (artificial intelligence),  go to poe.com and ask it anything!] 

Edwin