Which statement about satellite navigation is TRUE?

A
While a fix can be generated by signals received from two satellites, three satellites are necessary for reliable accuracy.
B
The satellites are in equatorial orbits around the earth about 60° of longitude apart.
C
The satellite navigation system determines a fix by measuring the doppler shift of the radio signals from the satellite.
D
The ship's receiver cannot begin processing data until the antenna locks onto the satellite and starts continuous tracking.
E