Write a task to do this C program

Watch the 2 video segments on functions:  11,  12

A.     Write a function that takes an array of ints, and the size of the array – another int.  It also returns a double.  Call this one ‘average.’  Return a double that is the average of the values in the array.  Demonstrate that it works by finding the average of an array with these values {78, 90, 56, 99, 88, 68, 92}

B.     Write a function that takes one double parameter, and returns a char.  The parameter represents a grade, and the char represents the corresponding letter grade.  If you pass in 90, the char returned will be ‘A’.  If you pass in 58.67, the char returned will be an ‘F’ etc.  Use the grading scheme on the syllabus for this course to decide what letter to return.

Write a function that takes 3 int arguments and returns the largest of the 3.