Vapour density of a compound is 39. It contains carbon and hydrogen atoms in the ratio 1:1. Its molecular formula is

given ratio of carbon and hydrogen atoms 1:1.

Let the molecular formula = $(CH{)}_n$.

Molar mass of the compound = (12+1) times n=13 n.

Molar mass = 2 $\times \text{ vapour density }$.

$\therefore 13n=2\times 39$

n=6.

So, the molecular formula is $C_6{H}_6$.

Therefore, option C is correct.