In an Isolated System of Two Bodies That Exert Gravitational

Multiple Choice

In an isolated system of two bodies that exert gravitational forces on one another, the quantity (quantities) that remain(s) constant is(are)

A) the total energy of the system.
B) the total angular momentum of the system.
C) the angular positions of the two bodies.
D) all of the above.
E) only (a) and (b) above.