When the sensing crystals contained in the thermoluminescent dosimeter are irradiated, which of the following occurs?

a. The protons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to a higher energy level or bands.
b. The neutrons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to a higher energy level or bands.
c. Some of the electrons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to higher energy levels or bands.
d. The electrons freed from the LiF molecule are trapped at a lower energy level or bands.

c. Some of the electrons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to higher energy levels or bands.