Answer:
C An electron moves from an upper energy level to a lower one
Step-by-step explanation:
When an atom absorbs a photon containing energy, any of the following can happen:
A- The atom is ionized: this can occur if an electron in the outermost shell absorbs the photon, and if the energy given by the photon is enough the free the electron, then the atom loses one negative charge, so it becomes ionised
B- An electron moves from a lower energy level to an upper one: this occurs if an electron in one of the shells absorbs the photon, and the energy of the photon is equal to the difference in energy of the current electron's level and one of the upper levels, so the electron jumps into that upper energy level
D- The atom becomes excited. This can occur if the photon is absorbed by the nucleus, so the nucleus goes into a higher energy state
While the following situation
C An electron moves from an upper energy level to a lower one.
does not occur, since in this case the photon would be released by the atom, not absorbed.