Which of the following cannot give a yellow $ppt.$ with $I_2/NaOH$?

Treatment of propionaldehyde with dilute $NaOH$ solution gives:

In the scheme given below,the total number of intra molecular aldol condensation products formed from '$Y$' is

Propyne was subjected to a reaction with $HgSO_4/dil. H_2SO_4$,which resulted in a product $P$. The product $P$ was heated with $Ba(OH)_2$ to give the product $Q$. The molecular formula of the product $Q$ is

$CH_3-CH_2-CHO \xrightarrow{Red\,P + HI} A$. Product $A$ is:

Identify the major product '$A$' formed in the following reaction:
$CH_3COCH_2CH(CH_3)CH_2Br \xrightarrow[(ii) H_2O]{(i) Mg} 'A'$