When Viewed from Earth, the Apparent Angular Diameter of Jupiter

Multiple Choice

When viewed from Earth, the apparent angular diameter of Jupiter appears to vary with time because

A) the amount of sunlight reaching Jupiter varies with time.
B) the absorption of radiation by interplanetary dust between Jupiter and Earth varies with time.
C) Jupiter is a fluid planet, and its size and brightness both pulsate with a long oscillation period.
D) the distance between Jupiter and Earth varies.