Final answer:
Option (C), The IRS standard mileage rate for business use of a vehicle in 2018 was 54.5 cents per mile, which encompasses all vehicle operating costs including fuel. The provided options do not correspond to this rate.
Step-by-step explanation:
The IRS approved rate for employer provided fuel for 2018 is not directly provided in the typical IRS notices for standard mileage rates. However, the standard mileage rate for business use of a vehicle in 2018 was 54.5 cents per mile. This rate is meant to cover not just fuel costs, but also wear and tear, and other vehicle operating expenses.
The options provided (5 cents, 5.5 cents, 55.5 cents, and 58.5 cents per mile) do not directly correspond to the standard mileage rate for 2018. For the most accurate and current information, it is best to refer directly to IRS documentation or their official website.