Answer
a) CH is the correct answer.
Work Step by Step
1. Assume a 100 g sample and calculate the amount of moles.
C:
$$ 92.3 \space g \times \frac{1 \space mole}{ 12.01 \space g} = 7.7
\space moles$$
H:
$$ 7.7 \space g \times \frac{1 \space mole}{ 1.008 \space g} = 7.6 \space moles$$
2. The formula is $C_{7.7}H_{7.6}$.
3. Dividing both numbers by 7.6: $C_{1.01}H_{1}$, which we can approximate to $C_1H_1$ or CH.
