A. switch it off
Feedback The phrasal verb 'switch off' has two meanings:1) to cause (a device - a light, television, etc.) to stop operating by or as if by moving a switch, knob, or lever; turnoff an electrical device: Have you switched the computer off?; I parked the car and switched off the engine.;2) (informal) to stop giving your attention to someone or something; make or become bored, alienated, etc:I'm afraid I just switch off when she starts telling me about her problems.; He just switches off and ignores me.According to the context of the test sentence (If you aren't watching TV…), we understand that the first meaning of this phrasal verb is used – ‘turn off an electrical device’, thus, we choose ANSWER 1.