$1.2 \mathrm{g}$ of organic compound on kjeldahlization liberates ammonia which consumes $30 {\mathrm{cm}}^3$ of $0.1 \mathrm{N}$ $\mathrm{HCl}$. The percentage of nitrogen in the compound is

The correct IUPAC name for ${\mathrm{CH}}_2=\mathrm{CH}-{\mathrm{CH}}_2-\mathrm{C}\equiv \mathrm{CH}$ is _____.

$\mathrm{A} :$ pent-$1$-en-$4$-yne

$\mathrm{B} :$ pent-$4$-en-$1$-yne

$\mathrm{C} :$pent-1-yne-1ene

Enter your correct answer as $\mathrm{A}, \mathrm{B} \mathrm{or} \mathrm{C}$.