Astronomers Can Determine the Maximum Size of a Distant, Luminous

Multiple Choice

Astronomers can determine the maximum size of a distant, luminous object by

A) directly resolving it in a telescope only.
B) using trigonometric parallax.
C) timing the fluctuations in its luminosity.
D) looking for the amplitude of an oscillating Doppler shift.
E) using the phenomenon of radio wave diffraction.