Predict the product (major)

Explanation

Out of `CH_(3)-overset(O)overset(||)C-H` (A) and `CH_(3)-CH=CH-overset(O)overset(||)C-H` (B), (B) aldehyde has more acidic hydrogen since the conjugate base is more resonance stabilized.

So, keep in mind, it is the more acidic hydrogen which is removed in aldol, it is not necessarily `alpha`-H. In this case, it is `gamma`-hydrogen (you know which one is more acidic - the one after the removed of which it is more stabilized, i.e. the conjugate base is more stabillized. Now, the product will be.