When a Positronium Atom Decays, It Emits Two Photons

Multiple Choice

When a positronium atom decays, it emits two photons. What are the energies of the photons?

A) 0.256 MeV and 0.256 MeV
B) 0.511 MeV and 1.022 MeV
C) 0.225 MeV and 0.285 MeV
D) 0.511 MeV and 0.511 MeV
E) 1.02 GeV and 938. MeV