Rohit and Mohit are partners in a firm sharing profits in the ratio of $5:3$. They admit Bijoy as a new partner for $\frac{1}{7}\text{th}$ share in the profits. The new profit sharing ratio will be $4:2:1$. The sacrificing ratio of Rohit and Mohit is-

1. A
   $2:5$
2. B
   $3:5$
3. C
   $4:5$
4. D
   $5:3$