Which statement best describes how a Geiger counter works? Select one:
a. Water vapor condenses along a path traveled by ionizing radiation.
b. Particles ionized by radiation cause black streaks to appear on sensitive photographic paper.
c. Radioactive particles ionize argon gas in a tube and the resulting electric current is amplified and heard as a clicking sound.
d. A material sensitive to radioactive emissions glows when mixed with a radioactive substance.