Objects a and B Interact with Each Other Via Both

Multiple Choice

Objects A and B interact with each other via both conservative and nonconservative forces. Let K_A and K_B be the kinetic energies, U be the potential energy, and E_int be the internal energy. If no external agent does work on the objects then:

A) K_A + U is conserved
B) K_A + U + E_int is conserved
C) K_A + K_B + E_int is conserved
D) K_A + K_B + U is conserved
E) K_A + K_B + U + E_int is conserved