Door Actuator failure

Hello, I have a problem with my door locks not working properly. My local mechanic told me the door actuators need replaced. I want to buy them and just have them installed, but I'm not sure how many are in the SUV? My front drivers side door works properly, but the front passenger and both rear doors do not lock/unlock electronically by either the fob or the interior button.

My question, are there 2 or 4 door actuators in my vehicle?

Thank you,
Alan P.