A construction company spends ww weeks extending an existing road.  The existing road is 7 miles long.  Each week the company completes 0.5 miles of the extension.  Which equation models the total length, LL , of the road over time?  A L=0.5w+7L=0.5w+7 B L=0.5w−7L=0.5w-7 C W=0.5L+7W=0.5L+7 D W=0.5L−