Code in c

Please give details about why you choose to do things a certain way.

4. Write recursive functions that list all of the one-element, twO-el three-element subsets of a given set of letters. For example em ent, one ele subs ("ACEG") fA) fcy E) two ele subs ("ACEG") (, } A, Eh A, G (C, EH (C, G IE, GH three_ele_subs ("ACEG") A, C, E) A, C, G) A, E, G) (C, E, G) Requirements: You must follow the description in the book. You must get the input string from the command line. You must print an error and exit if there is no string on the command line. This program must only accept 4-character strings (xxxx). You must print an error msg and end the program if you get more or less characters in a string. Your printout will have 3 separate tables: 1 element subsets, 2 element subsets, and 3 element subsets. You will print these one after the other (not next to each as is shown in the book). You will make 4 runs with the following inputs: ACEG, BETA, ALPHA, NO GLOBALS