$HC \equiv CH\mathop {\xrightarrow{{30\%\, {H_2}S{O_4}}}}\limits_{HgS{O_4}} A\xrightarrow{{NaOH}}B$
$CH_3CHO$ $+$ $CH_2(COOH)_2$ $\xrightarrow {\Delta}$ $X$
$[Figure]$ $\xrightarrow[{(ii){H_2}O}]{{(i)\,{C_2}{H_5}MgBr}}A\xrightarrow{{HCl}}B$