Time, as Indicated by an Uncorrected Sundial, Can Differ from True

Time, as indicated by an uncorrected sundial, can differ from true time by as much as 15 minutes at certain times of the year. This is because:

A) Earth moves non-uniformly along an orbit inclined to the celestial equator.
B) the Sun moves with respect to the background stars because of our motion on an orbiting Earth.
C) the time zones are poorly defined on Earth's surface, leading to time errors that vary through the year.
D) Earth's rotation rate varies throughout the year.