What is the escort ratio for airside, sterile, controlled area, and vehicle, respectively?

a) 1:1, 1:2, 1:3, 1:4
b) 1:2, 1:3, 1:4, 1:5
c) 1:3, 1:4, 1:5, 1:6
d) 1:4, 1:5, 1:6, 1:7