All of the Following Are True of Intraplate Earthquakes EXCEPT

All of the following are true of intraplate earthquakes EXCEPT:

A) they occur in extremely brittle rocks, and their effects are often felt over a wider area than those of plate boundary earthquakes.
B) they occur in areas of the Earth's crust that are already weakened by numerous faults.
C) they almost always occur at the surface, and are readily observable.
D) they are generally shallow, with a focus less than 30 miles deep.