Answer:
A) 3 to 2
Step-by-step explanation:
The Balmer series refers to all transition series of spectral emission lines of the hydrogen atom in which an electron moves from any higher energy level within the atom down to the energy level with principal quantum number n=2.
The Balmer series was originally calculated using the Balmer formula, this is an empirical equation first deduced by Johann Balmer in 1885.
Hence, a transition from n=3 level to n=2 level is in the Balmer series.