Part of the Energy Level Diagram of a Certain Atom

Multiple Choice

Part of the energy level diagram of a certain atom is shown below.The energy spacing between levels 1 and 2 is twice that between 2 and 3.If an electron makes a transition from level 3 to level 2,the radiation of wavelength λ is emitted. What possible radiation wavelengths might be produced by other transitions between the three energy levels?

A) both λ/2 and λ/3
B) only λ/2
C) both 2λ and 3λ
D) only 2λ