a) Differentiate between local variable and global variable. (2 marks} b) Write a C++ program segments for each of the following problems: 0 function denition studGrade (II that receives a student's mark and returns A if a student's mark is in range 80 - 100. B if the mark is in range 65 -79. C if the mark is in range 50 - 64 and D it the mark is below than 50. (6 marks} function prototype for the function denition in question 2 b) (i). (2 marks) program segment that will input the smdent's mark and then call the function denition in question 2 b) (i) and display the student's grade. (2 marks)