This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to clean a gas grill
Turn off the gas supply to the grill.
You do not want to have dangerous gasses build up during the cleaning process that can lead to injury.
Locate the gas supply valve on the propane tank for lp grills and where the grill connects to the house for lng supplied grills.

OPTIONS:
(a). Quickly close the valve so the valve is open. Turn on the gas supply valve and remove the cooking oil from the engine to a safe place to put it in your grill.
(b). On lp grills, the primary fuel source is lp. Change the fuel source by removing the d valve located at the bottom of the tank and turning it counterclockwise, which should turn it off.
(c). Wait two to three days for the grill to reach temperature and the fillers. You can light and grill the grill during a small amount of time.
(d). Turn the knob or lever clockwise to shut off the gas supply running into the grill. Remember " righty-tighty, lefty-loosey " to close and open valves.
The answer is:
(d).