Refer to figure.
Spoilers (also known as airbrakes) are surfaces that extend upwards from the upper surface of the wing. They are used to intentionally disrupt the smooth, laminar airflow over the wing. When deployed, they decrease the lift and increase the drag significantly. Spoilers can be used in several different ways, during flight and on the ground as;

• Flight spoilers/speed brakes: The spoilers on both wings are extended symmetrically - this increases the drag, allowing for a steeper descent gradient or reduction in speed. It can also be used to prevent Mach Tuck.
• Ground spoilers/Lift dumpers: On touchdown when landing, the spoilers extend symmetrically to their fully extended position. This greatly reduces the lift produced by the wings, applying weight on the wheels and allowing for greater breaking efficiency. It can also prevent the aircraft from bouncing or getting airborne again after touchdown.
• Roll Spoilers: The spoilers can be extended asymmetrically, so that the lift is reduced on one wing, but not the other. This will create a rolling moment and can be used for lateral control of the aircraft. This is usually used in conjunction with the ailerons during normal operations, but can also be used to achieve roll control in the event of aileron failure.

The other options listed do not match what is shown in the image. A slot is a leading-edge device that helps delay stall by allowing high-pressure air from below the wing to flow over the top surface. An aileron is a trailing-edge control surface used to control roll by increasing lift on one wing and decreasing it on the other. An elevator is part of the horizontal stabiliser on the tailplane and is used to control pitch, not found on the wing.