A car travels 110 miles / 2 hours. What is the unit rate?
A. 2 hours per 110 miles
B. 110 miles per 2 hours
C. one mile per 55 hours
D. 55 miles per hour
A. 2 hours per 110 miles
B. 110 miles per 2 hours
C. one mile per 55 hours
D. 55 miles per hour