The answer is:
[C]: 61.38 cm .
_______________________________________________Note: A =

²
300 = (3.14) * r² ;
______________________
Divide each side by "3.14" ;
r² = 300/3.14 ;
r² = 95.5414012738853503 ;
√r² = √(95.5414012738853503) ;
r = 9.7745281867661188048
Circumference, "C" =

* d ; (d = diameter = 2*r);
C = 2*

*r ;
C = 2*(3.14)*(9.7745281867661188048)
C = 61.384037012891226094144 ; which rounds to answer choice: [C]: 61.38 cm .________________________________________________________