The answer is B.16 : 52.
Let's compare all ratios to 4 : 13.
A. In order to be equivalent to 4 : 13 the ratio should be 8 : 26
4 : 13 = (4×2) : (13×2) = 8 : 26
B. In order to be equivalent to 4 : 13 the ratio should be 16 : 52
4 : 13 = (4×4) : (13×4) = 16 : 52 - Thus, this is the right choice.
C. In order to be equivalent to 4 : 13 the ratio should be 12 : 39
4 : 13 = (4×3) : (13×3) = 12 : 39
D. In order to be equivalent to 4 : 13 the ratio should be 20 : 65
4 : 13 = (4×5) : (13×5) = 20 : 65
