Three Galaxies, Each of Mass M = 4

Multiple Choice

Three galaxies, each of mass M = 4.0 * 1041 kg, lie in a plane at the corners of an equilateral triangle with sides of 5.0 *1022 m length. The magnitude of the force the other two galaxies exert on each galaxy is:

A) 4.3 *1027 N.
B) 6.4 * 1027 N.
C) 7.4 *1027 N.
D) 8.6 * 1027 N.
E) 4.3 * 1028 N.