In a nuclear reaction, two deuterium nuclei fuse to form a helium nucleus. Which of the following correctly describes the reason for energy release?

When two deuterium nuclei undergo nuclear fusion to form a helium nucleus, the total binding energy of the resulting helium nucleus is greater than the combined binding energy of the two original deuterium nuclei. This increase in binding energy per nucleon means the final nucleus is more stable, and the difference in mass (mass defect) is released as energy according to Einstein’s equation E = Δmc². This is the fundamental reason for the energy release in fusion reactions.