Final answer:
Destructors are commonly used for freeing allocated memory to prevent memory leaks when an object is destroyed. They are not responsible for memory allocation, members initialization, or managing inheritance.
Step-by-step explanation:
The common purpose of a destructor function in object-oriented programming is C) Freeing allocated memory. When an object goes out of scope or is explicitly deleted, the destructor is called to perform necessary cleanup tasks. The most frequent use of a destructor is to free any memory that was dynamically allocated by the object, ensuring that the program does not leak memory.
For example, if an object allocates memory for a data member during its construction (say, through new or malloc in languages like C++), it is the responsibility of that object's destructor to release that memory using delete or free. Otherwise, the memory would remain allocated even after the object is no longer in use, leading to a memory leak.
It is important to note that destructors are not used for allocating memory, initializing object members, or managing inheritance. Those tasks are handled respectively by constructors, member initializer lists, and class definitions or inheritance hierarchies.