#include<stdio.h>

/* Function declaration */
float calculateCircleArea(float);

int main() {
    float radius, area;

    printf("Enter the value of Radius: ");
    scanf("%f", &radius);

    area = calculateCircleArea(radius);

    printf("\nArea of the circle: %f", area);

    return 0;
}

/* Function definition to calculate area of circle */
float calculateCircleArea(float radius) {
    float area;
    area = 3.14 * radius * radius;
    return area;
}
 

Correct Answer: (d) #define PI 3.14

Explanation: #define is a pre-processor directive. #define is used to define something, for example, we have defined that PI is 3.14. Before going to the compiler, if ‘PI’ comes into the program, then it will be replaced by 3.14.

#define PI 3.14 is a macro preprocessor, it is a textual substitution.

Firmware is that program which is burned into the ROM of a device.

The short explanation of Firmware:

Firmware is a software program which is permanently inscribed into hardware devices include a keyboard, hard drive, BIOS etc. At the time of manufacturing Firmware is added to these devices. Actually, it gives permanent instructions to covey to other devices. So, it performs the basic input and output functions.