Which reaction intermediate is formed during the condensation reaction between acetaldehyde and formaldehyde?

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:

Which of the following does $NOT$ give a yellow precipitate when reacted with a $(NaOH + I_{2})$ mixture?

How can $A$ and $B$ be differentiated?

Which of the following is obtained when chloral is boiled with $NaOH$?

Ethylene is converted to $X$ on passing through a mixture of an acidified aqueous solution of palladium chloride and cupric chloride. Which of the following reagents readily take part in addition reaction with $X$?