Organic synthesis — practice question

$3$-oxobutanoic acid may be prepared in a two-step route. $X \rightarrow Y \rightarrow \text{3-oxobutanoic acid}$ What might the structure of $X$ be?

• A1, 2 and 3 are correct
• B1 and 2 only are correct
• C2 and 3 only are correct
• D1 only is correct