An Observer Located Outside Our Solar System, Who Monitors the Velocity

Multiple Choice

An observer located outside our Solar System, who monitors the velocity of our Sun over time, will find that its velocity varies by $\pm$ 12 m/s over a period of 12 years, because of:

A) Jupiter's gravitational pull
B) Earth's gravitational pull
C) variations in its brightness
D) convection on the Sun's surface
E) the sunspot cycle