physics: can you give me detailed solution: 15) What is state in the O2 molecule?

physics: can you give me detailed solution:

15) What is state in the O2 molecule? (The bond length in O2 is 0.121 nm and the mass of O atoms is 16u.)

the energy of a photon emitted in the transition from the l=3 rotational state to the l=2

a. 0.00107 eV

b. 0.00144 eV

c. 0.000960 eV

d. 0.000423 eV

e. none of the above