An electron is trapped using lasers $($you don't need to know details about this!$).$ All you need to know is that the electron has $3$ states, with energies as follows:

State $1$: $4\mathrm{.}1$ eV

State $2$: $4\mathrm{.}2$ eV

State $3$: $4\mathrm{.}3$ eV

It is in equilibrium with a reservoir at temperature $1090$ K$.$