$(a)$ $PhCOOH$
$(B)$ $o-NO_2C_6H_4COOH$
$(C)$ $p-NO_2C_6H_4COOH$
$(D)$ $m-NO_2C_6H_4COOH$
$(CH_3)_2CHCH_2C \equiv N \xrightarrow{HCl,{{H}_{2}}O}$ સંયોજન $A \xrightarrow[2.\,{{H}_{2}}O]{1.\,LiAl{{H}_{4}}}$ સંયોજન $B \xrightarrow[C{{H}_{2}}C{{l}_{2}}]{PCC}$ સંયોજન $C$

