Right answer: el acelerador
El acelerador (the acelerator or gas pedal) is the device that increases the flow of fuel to the engine of the car, this increases the volatility of the explosion inside the cylinders, which therebay increases the number of revolutions per minute (RPM) of the engine.
In other words:
When the car is moving, the result of pressing the accelerator will be a higher speed.
The other options are incorrect:
vidrio delantero y trasero (front and rear glass)
luces delanteras y traseras (front and rear lights)
maletero (boot or trunk)
tablero de mando (dashboard)
palanca de cambio (gearshift or gear lever)
because do not help to increase the speed of the vehicle