Answer : Here, The correct answer of this question will be option (D) Two.
Explanation :
$100 g$ of alkaloid contain nitrogen $=17.28 g$
$162 g$ of alkaloid contian introgen $=\frac{17.28 \times 162}{100}=27.99=28 g$
or one mole of alkaloid contain $28 g$ nitrogen or $\frac{28}{14}=2 g$ atoms of nitrogen
$\therefore$ Number of nitrogen atoms in molecule of alkaloid $=2$