What Condition Is Necessary on Earth to See Eclipses of Stars

Multiple Choice

What condition is necessary on Earth to see eclipses of stars in binary star systems?

A) The stars must have very similar surface temperatures, whatever the inclination of their orbital plane to the line of sight, to see a significant eclipse.
B) The line of sight from Earth to the star system must be very close to perpendicular to the orbital plane of the stars.
C) The line of sight from Earth to the star system must be in or very close to the orbital plane of the stars.
D) One of the stars must be much bigger than the other so that it can hide its smaller companion when the orbital plane is at a large angle to the line of sight.