Resource driven.

See this response:

From Primavera:

P3 3.1
Driving resource means a resource that determines the duration of the
activity to which it is assigned. P3 automatically calculates the
activity duration based on the quantity to complete and the units per
timeperiod of the driving resource. P3 schedules independent and
meeting activities using the resource calendars of their driving
resources.
Defining a resource as driving or nondriving in the Resource Dictionary
only establishes its default status; you can change it for any specific
assignment.

P3e
A resource that determines the duration of the activity to which it is
assigned. The Project Management module automatically calculates the
activity duration based on the quantity to complete and the units per
timeperiod of the driving resource.

Defining resources as driving, by marking the Drive Activity Dates by
Default checkbox for new resource assignments in the Projects window,
Project Details, Resources tab, only establishes its default status;
you can change it for any specific assignment.

If an activity has more than one driving resource, the resource that
takes the longest to complete determines the duration of the activity.

Regards

Marcio Eduardo