${?}^{1}H$ NMR of Compound B $(C_8{H}_{8}O)$ :

$A=C_8{H}_{10}O$

$2\mathrm{.}6-2\mathrm{.}9$ ppm $c=2HB=C_8{H}_{8}OB=C_8{H}_{8}O$

$7\mathrm{.}0-7\mathrm{.}45$ ppm b $=5H,$ multiplet

$2\mathrm{.}7-2\mathrm{.}8$ ppm $c=2H,$ doublet IR of Compound B $(C_8{H}_{8}O)$ :