Answer:
Methyl ethyl ketone
Explanation:
Compound 'A' forms phenyl hydrazone, so it must be a carbonyl compound. Since it also gives a negative iodoform test, so it can't be an aldehyde.
'A' on reduction gives propane. So, it must be butanone. Ketone reacts with phenyl hydrazine to form phenyl hydrazone but gives a negative iodoform test.
Thus, the correct answer is - Methyl ethyl ketone
