The Diagram Illustrates Physical Size and Angular Size as Seen

Multiple Choice

The diagram illustrates physical size and angular size as seen by the observer. We can estimate the size in light years (or parsecs or km) of M31 from

A) its angular size in degrees.
B) its distance in light years (or parsecs or km) .
C) its angular size in degrees and its distance in light years (or parsecs or km) .
D) It is impossible to estimate the size of M31.