Which type of variable is visible to every module and the entire program?

Hello my name is mihai and i need your : )i have to do a python project in computer science and i’m really busy with my mocks this period of time besides this i’m not good at coding so could someone pls pls pls sort me out ? i actually beg ; ))

Kyle, a receptionist for a building supply company, recently won an award for saving his company money on their phone system. after being presented with kyle's research, the company changed the way in which it made long-distance phone calls and cut their expenses in this area by 75 percent. the new system the kyle's company most likely adopted was wired communications switching stations voip hdtv

1)consider the following code snippet: #ifndef book_h#define book_hconst double max_cost = 1000.0; class book{public: book(); book(double new_cost); void set_cost(double new_cost); double get_cost() const; private: double cost; }; double calculate_terms(book bk); #endifwhich of the following is correct? a)the header file is correct as given.b)the definition of max_cost should be removed since header files should not contain constants.c)the definition of book should be removed since header files should not contain class definitions.d)the body of the calculate_terms function should be added to the header file.