An Eclipsing Binary System Consists of

Multiple Choice

An eclipsing binary system consists of

A) two stars orbiting each other in which periodic spectral line shifts due to Doppler shift are measured.
B) two stars that are clearly resolved as separate but orbiting each other and obviously gravitationally bound to each other.
C) a star that is periodically eclipsed by the Moon.
D) two stars whose combined light output toward Earth varies regularly as one star periodically moves in front of the other.