Question

If A - B = A then which is false? (Could be one or more)
A. B = U-A
B. B={}
C. A=B={}
D. B ⊂ A and B ≠ {}

Answer 1

All of them can be true. The last three assume B is empty. Subtracting the elements of the empty set do not change the set. The first one says B is the complement of A. Removing the elements of the complement of A from A doesn't remove anything. I suspect choice D is off, since the empty set is ALWAYS a subset of every set. If B is not empty in choice D, then that would be the answer

Answer 2

Sorry, I misread D as B equals {}. The answer is D.