If you are sitting on a stationary bus, which frame of reference might make you think the bus has started moving? a. A car in the next lane passes the bus.
b A passenger moves to the back of the bus. c The bus driver turns to look through the windshield.
scd None of the above.

Since we are sitting in the bus, our current system is the bus

If any object outside our current system moves, we might think that our system has started moving

We are given the choices:

Passenger moving to the back of the bus: This passenger is moving in our current system. So, his movement will not make us think that the bus is moving

The bus driver turns to look through the windshield: The driver is part of our system and is moving moving within the system. So, we wont think that the bus is moving

A car in the next lane: This car is outside our current system and if it moves, we might think that our current system (the bus) has started moving

Therefore, the movement of a car in the next lane will make us think that the bus is moving