The frequency of light emitted for the transition n=4 to n=2 of He^+ is equal to the transition in H atom corresponding to which

The frequency of light emitted for the transition n=4 to n=2 of He⁺ is equal to the transition in H atom corresponding to which of the following

(a)n=3 to n=1 (b) n=2 to n=1 (c) n=3 to n=2 (d)n=4 to n=3

The frequency of light emitted for the transition n=4 to n=2 of He^+ is equal to the transition in H atom corresponding to which of the following