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What is this program exhibiting: "Call by Value" or "Call by Reference"

minn #include float cal_area(float r); int main(int argc, char** argv) { float area, r; 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 printf(" Enter the radius of circle:"); scanf("%f", &r); area cal_area(r); printf(" Area of circle with radius %f = %f", r, area); } float cal_area(float r) float result; result = 3.14 * r *r; return result; }