Write a C program which prompts the user with the following options at the command prompt: 1) Compare two numbers for the larger, 2) Test a number for prime or not. After choosing the option program will ask user to enter any two integers and perform the operation as given in the options.

Here's a C program that prompts the user with the given options and performs the corresponding actions after taking input from the user:

#include <stdio.h>

// Function to compare two numbers and return the larger one
int compareNumbers(int num1, int num2) {
    return (num1 > num2) ? num1 : num2;
}

// Function to check if a number is prime
int isPrime(int num) {
    if (num <= 1) {
        return 0; // Not prime
    }
    for (int i = 2; i * i <= num; i++) {
        if (num % i == 0) {
            return 0; // Not prime
        }
    }
    return 1; // Prime
}

int main() {
    int choice, num1, num2;

    // Prompt user with options
    printf("Choose an option:\n");
    printf("1) Compare two numbers for the larger\n");
    printf("2) Test a number for prime or not\n");
    printf("Enter your choice (1 or 2): ");
    scanf("%d", &choice);

    switch (choice) {
        case 1:
            // Input two numbers
            printf("Enter two numbers: ");
            scanf("%d %d", &num1, &num2);
            // Compare and print the larger number
            printf("The larger number is: %d\n", compareNumbers(num1, num2));
            break;
        case 2:
            // Input a number
            printf("Enter a number: ");
            scanf("%d", &num1);
            // Check if the number is prime and print the result
            if (isPrime(num1)) {
                printf("%d is a prime number.\n", num1);
            } else {
                printf("%d is not a prime number.\n", num1);
            }
            break;
        default:
            printf("Invalid choice. Please enter 1 or 2.\n");
    }

    return 0;
}

This program prompts the user with options to compare two numbers for the larger or test a number for being prime. After the user chooses an option, it asks the user to enter the required numbers and performs the corresponding operation.