The number of benzene derivatives of the formula ${\mathrm{C}}_7{\mathrm{H}}_8\mathrm{O}$ is:

Product is :

The compounds $\mathrm{A}$ and $\mathrm{B}$ in the above reaction sequence are:

In the reaction sequence,

$\mathrm{A},\mathrm{B},\mathrm{C}$ and $\mathrm{D}$ are given by the set:

$\mathrm{Phenol} \underset{\mathrm{distilation}}{\overset{ \mathrm{zinc} }{\to }} \left(\mathrm{A}\right) \underset{\mathrm{Conc}.\mathrm{H}{ }_2{\mathrm{SO}}_4 \mathrm{at} 60°\mathrm{C}}{\overset{\mathrm{Conc}.{\mathrm{HNO}}_3}{\to }} \left(\mathrm{B}\right) \underset{\mathrm{NaOH}}{\overset{\mathrm{Zn}}{\to }} \left(\mathrm{C}\right)$

In the above reaction, products $\left(\mathrm{A}\right),\left(\mathrm{B}\right)$ and $\left(\mathrm{C}\right)$ are:

The product $\text{'}\mathrm{X}\text{'}$ is: