Nitration mixture is

The term "nitrating mixture" refers to the 1:1 mixture of concentrated nitric acid and sulfuric acid used to nitrate organic molecules such aromatic compounds and ${\mathrm{HNO}}_3$. The mixture of ${\mathrm{HNO}}_3 \mathrm{and} {\mathrm{H}}_2{\mathrm{SO}}_4$ is known as nitration mixture. 

Hence option (B) $1:1\text{ of conc. }{\mathrm{HNO}}_3\text{ and conc. }{\mathrm{H}}_2{\mathrm{SO}}_4$