in c language

Write a program to determine which of three letters comes first in alphabetical order. Assume that the user properly enters three lower-case letters. Program Requirements: - Prompt the user to enter three lower-case letters from the keyboard. - Determine which character comes first in alphabetical order. - Output the character to the screen. Sample program output: Enter three lower-case letters: a c f The letter that comes first in alphabetical order is a. Enter three lower-case letters: kgn The letter that comes first in alphabetical order is g. Enter three lower-case letters: zyx The letter that comes first in alphabetical order is x