Question

Which pairs are enantiomers?

Are the pairs A&C, A&B, B&C, B&D enantiomers?

Answer 1

Enantiomers are non-superimposable mirror images of each other.

A good heuristic is to assign absolute configurations, and find the pair with the same orientation/configurations.

From that data, we can determine that `("A")` and `("B")`, as well as `("C")` and `("D")` are enantiomers.

Out of your choices, it seems as though "A&B" is correct.