#include &lt;iostream&gt;    using namespace std;    #define PI 3.14159    int main &#40;&#41;    &#123;        float r = 2;        float circle;        circle = 2 * PI * r;        cout &lt;&lt; circle;        return 0;    &#125;
A. 12.5664
B. 13.5664
C. 10
D. compile time error
Answer:A
#include &lt;iostream&gt;    using namespace std;    #define PI 3.14159    int main &#40;&#41;    &#123;        float r = 2;        float circle;        circle = 2 * PI * r;        cout &lt;&lt; circle;        return 0;    &#125;
A. 12.5664 B. 13.5664 C. 10 D. compile time error
Explanation:In this program, we are finding the area of the circle by using concern formula.