What is formed when phenylacetylene reacts with dilute $HgSO_4$ in the presence of $H_2SO_4$?

An unknown compound $X$ is an unsaturated hydrocarbon. It reacts with $HgSO_4$ and $H_2SO_4$ to give compound $(B)$. Compound $(B)$ on oxidation gives compound $(C)$. Compound $(C)$ on reaction with $NaOH$ and soda lime gives methane. Identify $A$ (which is $X$),$B$,and $C$ by providing the chemical reactions.

When acetylene is passed through a solution of dilute sulfuric acid containing mercuric sulfate,the number of $\pi$ bonds in the final product obtained is.........

The major product of the following reaction is $P$. Number of oxygen atoms present in product $P$ is $. . . . . . . . . . . (nearest integer)$.

$CH_3-C \equiv CH \xrightarrow[(ii) H_2O_2/OH^{\Theta}]{(i) BH_3-THF} (P)$
$CH_3-C \equiv CH \xrightarrow[(ii) NaBH_4]{(i) Hg(OAc)_2/H_2O} (Q)$
Choose the correct option

What is the product obtained upon hydrogenation of the following compound in the presence of a poisoned palladium catalyst?