Summary of the article Eclipses

From the point of view of an individual on Earth, the Sun is overshadowed when the Moon separates it and Earth, and the Moon is obscured when it moves into the shadow of Earth cast by the Sun. Obscurations of common satellites (moons) or of rocket circling or flying past a planet happen as the bodies move into the planet's shadow. The two part stars of an overshadowing twofold star move around one another so that their orbital plane goes through or close to Earth, and each star intermittently obscures the different as observed from Earth.

C. c is the correct answer.