Question ATPL - Airline Transport Pilot license - Radio Navigation

ATPL - In order to measure the radial from a VOR, the aircraft VOR receiver

Measures the time difference between reception of the two signals transmitted from the ground installation.

Measures the phase difference between the reference phase and the variable phase of the signal.

Measures the time difference between sending the interrogation signal and receiving the transponder signal.

Uses pulse technique to determine the radial.