Write a program using C that prompts the user to enter a positive integer between 1 and 1000 (inclusive) and that outputs whether the number is prime. If the number is not prime, then output all the numbers, from the list of the first 11 prime integers, which divide the number.
a) Coding a prime number checker in C.
b) Implementing user input validation.
c) Generating a list of prime numbers.
d) Demonstrating programming skills in C.