A construction crew needs to build a road that will be 20 miles long. The crew already completed a stretch that is 6.44 miles long and another that is 8.62 miles long. Round each distance to the nearest mile. About how much more road does the construction crew need to build?
A.
about 5 mi

B.
about 6 mi

C.
about 7 mi

D.
about 9 mi