please answer in c language

a. Declare an array of size 20 and take input in an integer array from users using a loop. b. Write a function named "get_highest" which takes the array in (a) as parameter and returns the highest number in that array. c. Write a function named "get_average which takes the array in (a) as parameter returns the average of all the numbers in that array. d. Declare a 2D array that keeps calendar dates for month of September (of 2020). e. Initialize all the weekend dates to have value -1 and all the weekdays to have the value 1. 1 Add file