If molar mass of compound B is $\mathrm{x}$ then find $\frac{\mathrm{x}}{2}$

Solution

Molar mass of $\mathrm{B}=198=\mathrm{x}$
$\frac{\mathrm{x}}{2}=\frac{198}{2}=99.00$

Hence, the correct answer is 99.