The correct answer is: D. C is the brother of A.
Explanation:
- A is the brother of B.
- B is the brother of C.
- D is the father of A.
Based on these statements, we can definitely conclude that:
- A is the brother of B.
- B is the son of D.
- A is the brother of C.
- A, B, and C are D’s children.
However, we cannot definitely conclude that C is the brother of A. It is possible that C is the sister of A, or that C is not related to A at all.
For example, let’s say that A, B, and C are all adopted children of D. In this case, C would not be the brother of A, even though they are all children of D.
Another possibility is that C is the biological child of D, but A and B are not. In this case, C would be the brother of A and B, but they would not be siblings.
Therefore, the only statement that cannot be definitely true is D. C is the brother of A.