Where does the energy come from in this fusion reaction?

https://media.glynlyon.com/a_scichem_2011/4/21h1.gif

possible answers:
a small amount of mass converted to energy
a nuclear reactor
the energy needed to fuse the atoms together
an external source of power

Question

Where does the energy come from in this fusion reaction?

https://media.glynlyon.com/a_scichem_2011/4/21h1.gif

possible answers: 
a small amount of mass converted to energy
a nuclear reactor
the energy needed to fuse the atoms together
an external source of power

apoorvk · Answer

option. A.

Basically the mass difference from the reaction is converted into energy, acording to Einstein's E=(deltaM)C^2 law

anonymous · Answer

how about this one? https://media.glynlyon.com/a_scichem_2011/4/21h1.gif

apoorvk · Answer

same.