Suppose You Pick 100 Stars at Random from the Night

Multiple Choice

Suppose you pick 100 stars at random from the night sky and plot the apparent magnitude versus color ratio for these stars. What would this plot show you?

A) This is a color-magnitude diagram. By noting the turnoff point on the main sequence you could determine the age of the oldest star in the group.
B) Because we are not examining stars in a cluster, there will be no turnoff point. But you will have an H-R diagram with main sequence, giants, and white dwarves.
C) Because we are not examining stars in a cluster, there will be no turnoff point. It will be an H-R diagram, but with only 100 stars it is unlikely that more than one or two stars will be red giants.
D) Because we are plotting apparent magnitude versus color ratio for a group of unrelated stars, the plot will probably not show any particular pattern.