Which of the Following Is the Java Equivalent of the Following

Which of the following is the Java equivalent of the following mathematical expression? c = 2 $\pi$ . radius

A) c = 2 * Math.PI * radius * 2;
B) c = 2 * Math.PI * Math.pow(2, radius) ;
C) c = 2 * Math.PI * Math.pow(radius, 2) ;
D) c = 2 * Math.PI * radius;