To comply with IRS regulations, a taxpayer's mileage log must contain __________. a. Dates the vehicle was used for business; purpose of the trip; estimated miles traveled for business; estimated miles traveled for commuting; estimated total miles the vehicle was driven the entire year for all purposes. b. Dates the vehicle was used for business; miles traveled for business; total miles the vehicle was driven the entire year for all purposes. c. Dates the vehicle was used for business; purpose of the trip; miles traveled for business; miles traveled for commuting; total miles the vehicle was driven the entire year for all purposes. d. A mileage log is not needed. Taxpayer's may use an average of business miles per month to calculate the expense deduction