The front passenger airbag is usually located:

The front passenger airbag is typically located above the glove box in most vehicles. This positioning allows the airbag to deploy effectively in the event of a collision, providing a cushion for the passenger's safety. The airbag is housed in a compartment in the dashboard, which is designed to open quickly during deployment without hindering the passenger's space.

Other locations mentioned, such as inside the door or below the glove box, would not be ideal due to the space and design constraints required for effective airbag deployment. The airbag sensor option is also not a suitable answer, as the sensor is responsible for detecting a collision and triggering the airbag but is not the location of the airbag itself. Thus, above the glove box is the correct and common location for the front passenger airbag in vehicles.