Final answer:
The relative speed of a car to a van, with both vehicles traveling south and the car at 65 km/hr and the van at 50 km/hr, is 15 km/hr.
Step-by-step explanation:
The question is asking for the relative speed of the car with respect to the van. Since both the car and the van are traveling in the same direction, we can calculate the relative speed by finding the difference in their speeds. Thus, the relative speed of the car with respect to the van is 65 km/hr (car's speed) - 50 km/hr (van's speed), which equals 15 km/hr. Therefore, the correct answer is A. 15 km/hr.