In the Proton- Proton Cycle, the Helium Atom and Neutrino

Multiple Choice

In the proton- proton cycle, the helium atom and neutrino have less mass than the original hydrogen. What happens to the "lost" mass?

A) It is transformed into electrons.
B) It is recycled back into hydrogen.
C) It is converted to energy.
D) It is ejected into space.
E) Conservation of mass dictates no mass can be lost.