Final answer:
The subject of this question is Computer Science, specifically object-oriented programming in the context of defining classes and inheritance.
Step-by-step explanation:
The subject of this question is Computer Science, specifically object-oriented programming in the context of defining classes and inheritance. The question asks the student to define classes named Vehicle, Car, and Truck, with specific member functions and private variables. The student is also asked to prompt the user for details and create objects of the Car and Truck classes, and call the print function for each object.