When benzene ( 70 gm ) react with nitrating mixture and form product A , which further react with $\mathbf { B r } _ { \mathbf { 2 } }$ in presence of $\mathbf { F e }$ produce B. B on further show reduction with $\mathrm { Fe } / \mathrm { HCl }$ and after diazotization give C and C on reaction with $\mathrm { CuBr } / \mathrm { HBr }$ give product D. Find out mass of product D in gm.