The mean monthly salary paid to 75 workers in a factory is Rs. 5680. The mean salary of 25 of them is Rs. 5400 and that of 30 others is Rs. 5700. The mean salary of the remaining workers is.

A. Rs. 5000

B. Rs. 6000

C. Rs. 7000

D. Rs. 8000

Required average $\begin{array}{l} =\text { Rs. }\left[\Large\frac{(5680 \times 75)-\{(5400 \times 25)+(5700 \times 30)\}}{75-(25+30)}\right] \\ =\text { Rs. }\left[\Large\frac{426000-(135000+171000)}{20}\right] \\ =\text { Rs. }\left(\Large\frac{120000}{20}\right) \\ =\text { Rs. } 6000 \end{array}$