\(\therefore \mathrm{CH}_{3} \mathrm{COOH}+\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH} \stackrel{\mathrm{conc} \mathrm{H}_{3} \mathrm{SO}_{4}}{\longrightarrow}\)\(\mathrm{CH}_{3} \mathrm{COOC}_{2} \mathrm{H}_{5}+\mathrm{H}_{2} \mathrm{O}\)
$(a)$ $PhCOOH$
$(B)$ $o-NO_2C_6H_4COOH$
$(C)$ $p-NO_2C_6H_4COOH$
$(D)$ $m-NO_2C_6H_4COOH$