Assigning an object of a derived class to a variable of a base class is called:

A) static binding
B) dynamic binding
C) upcasting
D) downcasting

Assigning an object of a derived class to a variable of a base class is called upcasting. This is because the object of the derived class can be treated as if it were of the base class. Upcasting is a type of static binding, where the binding between the variable and the object happens at compile-time instead of run-time. Dynamic binding, on the other hand, is when the binding between the method call and the method to be invoked happens at run-time. Downcasting is the opposite of upcasting, where an object of a base class is assigned to a variable of a derived class.