A can't be true in this scenario, lets try to put U in slot 5.
We are told that W is immediately before X, so we have a sequence of V - Z - WX. We also know that Y is in the first 3 and U is in the last three.
This means that the final three must be some combination of W, X, and U. Additionally, since we know that W must be before X, there are actually only two possibilities:
_ _ _ U W X
_ _ _ W X U
Either way, one of the WX block must be in slot 5, so A is impossible.
