What is the definition of a study unit for Penn Foster?

Establish which of the following statements are true. (a) a sequence is convergent if and only if all of its subsequences are convergent. (b) a sequence is bounded if and only if all of its subsequences are bounded. (c) a sequence is monotonic if and only if all of its subsequences are monotonic.

Eye injuries usually occur as a result of all of the following things, except: a) proper machine operation b) battery explosion c) falling or flying debris d) electric welding arc

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.