X-ray images benefit from conditions that produce strong differential absorption. Which of the following processes is central to differential absorption? Select one:
a. An electron passes the nucleus of an atom, deviates and loses energy, producing an x-ray.
b. A photon interacts with an inner shell electron, where all x-ray energy is converted into producing a free electron and a characteristic x-ray.
c. An x-ray interacts with an outer shell electron of an atom, deviates and loses energy, and produces a photoelectron.
d. An incoming electron interacts with inner shell electrons, ejecting an electron from the atom and producing a characteristic x-ray.
e. An x-ray is deflected by low-Z atoms, producing a photoelectron.