In R Programming please help me fulfill the code for problem 7 a-d

7. Define the following functions: a. A function funcSum that accepts a numeric vector and returns the sum of the elements. Assume input will not have missing values, special values, and at least one element. A function funcIsPrime that accepts a numeric scalar (vector of length one) and returns TRUE is the input is a prime number and FALSE otherwise. Assume input will not have missing values, special values, and at least one element. A function funcCountNA that accepts a vector and returns the number of missing values (NAs) found in the vector. A function funcCountDENA that accepts two arguments: x, a data frame; and an option parameter count mode (default-1). If count_mode equals 1, then the function should return the total number of missing values in the entire input data b. c. d. frame; if count_mode equals 2, then the function should return the number of rows in which there is at least one missing value in the input data frame; if count_mode equals 3, then the function should return the number of columns in which there is at least one missing value in the input data frame. If x is not a data frame or is count_mode is not in the set {1, 2, 3), the function should return a NULL Hint: See help on length; sum; is.na; is.data.frame