A spinner is divided into many sections of equal size. Some sections are red, some are blue, and the remaining are green. The probability of the arrow landing on a section colored red is 9/20. The probability of the arrow landing on a section colored blue is 6/20. What is the probability of the arrow landing on a green-colored section
A. 15/20
B. 11/20
C. 6/20
D. 5/20