Convert propyne `(Me--=-H)` (A) to

Explanation

For solving such conversions, proceed backward (retrosynthetic analysis).

Preparation of (B) can be done by propinylation (type of ethinylation reaction).
First, convert propyne to propanal and then propinylation reaction.
Conversion of `Me--=-H` to
1. Catalytic hydration method will give ketone.
2. HBO reaction will give aldehyde (anti-Markovnikov's addition).