To prove the statement “if all A are B, then all C are D”, it suffices to show which of the following:
A. All A are D, and all B are C
B. All A are C, and all D are B
C. All C are A, and all B are D
D. All B are C, and all A are D
I'm confused by this problem. I tried all 4 answer choices and it seems to me that only C comes close to the correct answer. But if C is correct, then we have "all(all(all C)) are D", not "all C are D" (!?). Can someone help me solve it?
A. All A are D, and all B are C
B. All A are C, and all D are B
C. All C are A, and all B are D
D. All B are C, and all A are D
I'm confused by this problem. I tried all 4 answer choices and it seems to me that only C comes close to the correct answer. But if C is correct, then we have "all(all(all C)) are D", not "all C are D" (!?). Can someone help me solve it?