A meter stick supported at the 50 cm mark has masses of 300 g & 200 g hanging from it at the 10-cm & 60-cm mark, respectively. Where should we hang a third, 400-g mass to keep the meter stick balanced?
A. 0.30 m to the left of the point of support
B. 0.50 m above the point of support.
C. On the left end of the meter stick.
D. 0.25 m to the right of the point of support.