Which of the following is NOT a step to take before starting the engine?

Answer: C — Adjust stereo

Adjusting the stereo is not a necessary step to take before starting the engine. The focus before driving should be on ensuring the vehicle is safe and ready for operation. Adjusting the seat helps ensure that the driver can reach the pedals and controls comfortably and safely. Checking the windshield and windows is crucial for visibility; any obstructions or dirt can hinder the driver's ability to see the road clearly. Fastening seat belts is a critical safety measure that should be performed before starting to drive, as it protects occupants in the event of a collision. Therefore, while adjusting the stereo may enhance the driving experience, it does not contribute to the immediate safety or readiness of the vehicle in the same way the other actions do.