Answer
It should jump to the state $n = 5$
Work Step by Step
In the ground state state, $n = 1$
When the electron is in the third excited state, then $n = 4$
When an atom absorbs light, it can jump to a higher state where $n \gt 4$
Note that light with a longer wavelength has less energy than light with a shorter wavelength.
To absorb light with the longest possible wavelength, the electron must jump up to the state that is one step higher so that the energy difference between states is a minimum.
It should jump to the state $n = 5$
