$A$ sample of $0.125 \ g$ of an organic compound when analysed by Duma's method yields $22.78 \ mL$ of nitrogen gas collected over $KOH$ solution at $280 \ K$ and $759 \ mm \ Hg$. The percentage of nitrogen in the given organic compound is (Nearest integer).
$(a)$ The vapour pressure of water at $280 \ K$ is $14.2 \ mm \ Hg$
$(b)$ $R = 0.082 \ L \ atm \ K^{-1} \ mol^{-1}$

• A
  $22$
• B
  $23$
• C
  $21$
• D
  $20$