I'm going to use the convention that upper case refers to a name and lower case refers to an occupation and the symbol <> means 'not equal'.
The four statements are then:
B = s
C = b
D <> s
S <> d
Let us assume that the first statement is true, so the other three are false.
Given that the four True statements are:
B = s
C <> b
D = s
S = d
But if C <> b, and because C = c is not allowed by the problem statement, C = d or C = s. Either one of these statements contradicts D = s or S = d. Therefore the assumption that B = s is false.
Next, let us assume that the second statement is true, and the other three are false.
The four true statements are then:
B <> s
C = b
D = s
S = d
Since B <> s, it must be true that B = c or B = d, hence Baker is the carpenter because B = d contradicts S = d.
Next, let us assume that the third statement is true, leading to:
B <> s
C <> b
D <> s
S = d
B <> s means B = c or B = d. C <> b means C = s or C = d. And D <> s means D = b or D = c. B must equal c because B = d contradicts S = d. Then D = b and C = s. Again, Baker is the carpenter.
Lastly, let us assume that the fourth statement is true, leading to:
B <> s
C <> b
D = s
S <> d
Since D = s and C must then be d or s, C = d. S <> d means S = b or S = c and B <> s means B = c or B = d, so S = b and B = c. Again, Baker is the carpenter.
We don't know which of statements 2, 3, or 4 is true, but we do know for certain that Baker is the carpenter.
John

My calculator said it, I believe it, that settles it
