48. if you are traveling on the access road of a controlled-access highway, you must yield the right-of-way to

D. To both A and C are correct  

Any vehicle that is coming off the highway and any vehicle entering the controlled access highway.

Explanation:

A highway that is designed for high-speed vehicular traffic is known as controlled-access highway. All the traffic ingress and egress are regulated on such highways. Controlled access highways are also called as freeway, motorway and expressway in various countries. Such highways provide unhindered flow of traffic as there is no property access, intersection or traffic signals or at-grade crossing. Most of the crossing are carried by underpasses and overpasses.Such highways developed during the first half of 20th century.