Benzyl alcohol is obtained from benzaldehyde by:

Given below are two statements:
Statement $I$: $H_2N-CO-CH_2-CH_2-CO-CH_3$ under Clemmensen reduction conditions will give $HOOC-(CH_2)_3-CH_3$.
Statement $II$: $CH_3-CH(CH_3)-CH_2-CH(Cl)-CO-CH_3$ under Wolff-Kishner reduction conditions will give $CH_3-CH(CH_3)-CH_2-CH(Cl)-CH_2-CH_3$.
In the light of the above statements,choose the correct answer from the options given below:

The synthesis of crotonaldehyde from acetaldehyde is an example of ....... reaction.

How many compounds among the following give white crystals when reacted with sodium bisulphite $(NaHSO_3)$?
$1. HCHO$
$2. CH_3CHO$
$3. CH_3COCH_3$
$4. C_6H_5COCH_3$
$5. C_6H_5COC_6H_5$

What is the product formed when acetone reacts with $I_2$ in the presence of $NaOH$?

The product formed in Aldol condensation is