[单选题]
When a positronium atom (electron + positron) decays, it emits two jvvpi: yg79 7gphotons. olvgqg5e)7a +What are the energies of the pa)5gveq+7olg hotons?
A. 0.511 MeV and 1.022 MeV
B. 0.225 MeV and 0.285 MeV
C. 0.256 MeV and 0.256 MeV
D. 0.511 MeV and 0.511 MeV