The WeChat phone company provides the international call service to four (4) area codes. The charges (per-minutes rate) for the respective area code as following: Area Code 601 602 612 613 Rates (RM/minute) 0.20 0.30 0.60 0.50 Design a program in C++ to calculate the phone bill. Define a base class that allows user to enter an area code and duration for a call (in minutes) and then display the total cost of the call. If the total cost of the calls is more than RM100, a discount of MM% on the total cost of call will be given to the customer. Define a derived class to calculate the phone bill after discount. You have to include the constructor and destructor in your program too. Hints: MM - refer to the third and fourth digits of your student number. Example: if your student number is 0123438, then surcharge MM% will be 23%.