An Object of 3

Multiple Choice

An object of 3.0-kg mass is located at (0.0 m,8.0 m) ,and an object of 1.0-kg mass is located at (12 m,0.0 m) .You want to add a 4.0-kg object so that the center of mass of the three-object system will be at the origin.What should be the coordinates of the 4.0-kg object?

A) (-3.0 m, -6.0 m)
B) (-12 m, -8.0 m)
C) (3.0 m, 6.0 m)
D) (-6.0 m, -3.0 m)