How Does the Ionosphere Affect GPS

Multiple Choice

How does the ionosphere affect GPS?

A) GPS satellites orbit the Earth in the ionosphere.
B) GPS ground stations lose contact with geosynchronous satellites orbiting near the poles.
C) GPS signals must pass through the ionosphere,whose gases weaken the signal.
D) Positively charged ions in the ionosphere speed up the GPS signal,causing signal error.
E) Ionosphere gases strengthen GPS signals,improving locational accuracy.