[单选题]
When a positronium atom (electro9a*)k0dnx0zn( nmz g un + l2o hrr1 j/t+01sj4alq pjqw4 positron) decays, it emits two photons. What are the energies of the photons?2l jp4/q r4oltjsq 1+0rjh1wa
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