A massive particle X in free space decays spontaneously into two photons

Q. A massive particle X in free space decays spontaneously into two photons. Which of the following statements is true for X?

(A) X is charged

 (B) Spin of X must be greater than or equal to 2

 (C) X is a boson

 (D) X must be a baryon

Ans: X is a boson