Multi-choice problem: Continue writing the next sentence in this paragraph:

How to add oil to your car
Check the oil after the car has rested for 5 minutes.
If you check the oil right after turning the car off you will get an inaccurate reading, as some of the oil will still be at the top of the engine. Keep the car on a level, even surface as well to make sure you aren't checking the oil on a slant.

OPT: (a). If the top of the engine faces up, it is most likely heavy oil. If the top remains level, then it means that you have not put on enough oil.. (b). Refer to the owner's manual to determine if the oil is still at the top of the engine. Do not check oil more than 90 degrees to the side of the engine.. (c). Most auto manufacturers require you check the oil after the car has been warmed by starting it in place for 3-5 minutes. Check your owner's manual if there is any doubt.. (d). Turn the car onto a straight, level surface. Make sure you stay in the same place when doing this..
(c).