= 161051.


Option B).


Any of 11 letters in  the first position gives 11 options.

Any of 11 letters in  the second position gives 11 independent options.

. . . and so on . . . 


In all, it gives   = 161051 5-letter words.

There are 11 ways to choose the 1st letter.

For each of those 11 ways to choose the first letter,
there are 11 ways to choose the 2nd letter.
That's 11×11 or 121 ways to choose the first 2 letters.

For each of those 11×11 or 121 ways to choose the first 2 
letters, there are 11 ways to choose the 3rd letter.
That's 11×11×11 or 1331 ways to choose the first 3 letters.

For each of those 11×11×11 or 1331 ways to choose the first 
3 letters, there are 11 ways to choose the 4th letter.
That's 11×11×11×11 or 14641 ways to choose the first 4 
letters.

For each of those 11×11×11×11 or 14641 ways to choose the 
first 4 letters, there are 11 ways to choose the 5th letter.
That's 11×11×11×11×11 or 161,051 ways to choose all 5 letters.

Anawer:  11×11×11×11×11 = 115 = 161,051

Edwin