Select all true statements:
A.
Conservation of momentum can only be applied if there are no forces in any direction applied to the system.
B.
Kinetic energy is always conserved in a collision.
C.
The post impact velocity of the individual bodies is the same regardless of how elastic/plastic the collision is.
D.
The vector sum of the pre-impact momentum of the bodies is equal to the vector sum of the post impact momentum of the bodies.