For the Following Allowed Transitions, Which Photon Would Have the Largest

Multiple Choice

For the following allowed transitions, which photon would have the largest wavelength when an electron 'jumps' from one energy level, characterised by the quantum number n, to another?

A) n = 2 to n = 1
B) n = 3 to n = 2
C) n = 3 to n = 1
D) n = 1 to n = 3
E) n = 4 to n = 1