Which among the following has highest melting point ?

Which of the following alcohols on addition of Lucas reagent reacts fast and turns the reagent turbid instantly.

Which among the following does NOT undergo Williamson's synthesis?

Identify the product 'Y' in the following reaction $\text{Benzonitrile} \xrightarrow{\large{\text{C}_6\text{H}_5\text{MgBr} / \text{dry ether}}} X \xrightarrow{\large{\text{H}_3\text{O}^+}} Y + \text{MgBr(OH)} + \text{NH}_3$