When a traffic signal light is red, you must:

Answer: C — Stop and remain stopped until the light turns green

When a traffic signal light is red, you must stop and remain stopped until the light turns green. This is to ensure the safety of yourself and others on the road. Making a right turn on a red light is only allowed in certain situations and should not be considered as the default action. Making a left turn on a red light would be violating traffic laws and is not a safe option. Proceeding with caution on a red light can also be dangerous and should not be done. It is important to follow traffic signals to avoid accidents and maintain traffic flow.