Private data can be accessed by A. class member functions B. functions in derived classes C. both (a) and (b) D. neither (a) nor (b)

The correct answer is: C. both (a) and (b)

Private data can be accessed by class member functions and functions in derived classes.

Class member functions can access private data because they are part of the same class. Functions in derived classes can access private data because they inherit from the class that contains the private data.

Here is an example of how private data can be accessed by class member functions:

“`class Person {
private:
string name;
public:
void setName(string name) {
this->name = name;
}
string getName() {
return name;
}
};

int main() {
Person person;
person.setName(“John Doe”);
cout << person.getName() << endl; // prints “John Doe”
}
“`

In this example, the setName() and getName() functions are able to access the private name variable because they are part of the Person class.

Here is an example of how private data can be accessed by functions in derived classes:

“`class Person {
private:
string name;
public:
void setName(string name) {
this->name = name;
}
string getName() {
return name;
}
};

class Employee : public Person {
private:
int id;
public:
void setId(int id) {
this->id = id;
}
int getId() {
return id;
}
};

int main() {
Employee employee;

In this example, the setId() and getId() functions are able to access the private id variable because they are part of the Employee class, which inherits from the Person class.