Solar Flares,the Violent Eruptive Events on the Sun,occur MOST Frequently

Solar flares,the violent eruptive events on the Sun,occur MOST frequently:

A) over single, isolated, but large sunspots.
B) along the solar equator at positions aligned with Jupiter's position; they are caused by tidal disturbance on the Sun.
C) within solar coronal holes, from which the solar wind originates.
D) in or above complex sunspot groups.