$Ethyl \ methyl \ ketone$ is obtained by heating calcium salts of

The molecular formula of the final product of the following synthetic scheme is:

$CH_3-C(CH_3)(OH)-C(CH_3)(OH)-CH_3 \xrightarrow[H^{+}]{\Delta} ?$

Identify $Z$ in the following sequence of reactions.
$C_2H_4Br_2$ $\xrightarrow[\text{(ii) } NaNH_2]{\text{(i) alc- } KOH} X$ $\xrightarrow[\text{Red hot}]{\text{Fe tube, } 873 \ K} Y$ $\xrightarrow[\Delta]{\left(CH_3CO\right)_2O / \text{Anhyd-} AlCl_3} Z$

Which among the following compounds is treated with benzonitrile in dry ether followed by acid hydrolysis to obtain benzophenone?

$Ph-COOH$ $\xrightarrow{SOCl_2} (A)$ $\xrightarrow{H_2, Pd-BaSO_4} (B)$. Product $(B)$ is: