Question

indexing the rotor
is not important
means marking the rotor to the hub using a paint marker or crayon to keep the newly matched rotor and hub assembly positioned together correctly
repositioning the rotor on the hub after using a bench lathe to achieve the lowest lro
means marking the rotor and hub to keep them on the same side of the car as they started at

Explanation:

Indexing the rotor is a process to mark the rotor - hub assembly for correct positioning. It involves using a paint marker or crayon to mark the rotor to the hub so that the newly matched parts remain in the right position relative to each other.

Answer:

Means marking the rotor to the hub using a paint marker or crayon to keep the newly matched rotor and hub assembly positioned together correctly