Why Is the Moon's Synodic Period Longer Than Its Sidereal

Multiple Choice

Why is the Moon's synodic period longer than its sidereal period?

A) because most months have more than 27 days
B) because the Sun moves faster than the Moon
C) because Earth has moved along its orbit during a sidereal period
D) because one complete orbit of the Moon around Earth takes longer than the cycle of lunar phases