What is the purpose of the two radar altimeters in the cockpit?

The purpose of the two radar altimeters in the cockpit is primarily to serve as backups in case of failure. Having two radar altimeters ensures redundancy in the system, which is crucial for maintaining reliable altitude information during flight. In the event that one radar altimeter fails or provides erroneous data, the second altimeter can provide accurate readings, thereby enhancing safety and situational awareness for the pilot.

While the other options present functions associated with altitude measurement, the focal point of the redundancy feature ensures that both systems contribute to the overall reliability and safety of the flight operation. The other options do not accurately encapsulate the primary function of having two radar altimeters specifically for backup purposes.