as soon as possible please i need it in 10 mints

(a) Write the function void setupRandDNA (int n, char dna [ J) which creates a random DNA string of length n. Hint: DNA consists of letters. A C G T. Remember to terminate the string with ' \0 , (b) Write the function int getLetterCount (char strt, char letter), where str t) is a string and letter is a single character. The function returns how many times letter occurs in the string