Bernoulli's principle can be used to explain the lift force on an airplane wing. how must an airplane's wing be designed to ensure that bernoulli's principle is applicable?

Below are the choices that can be found from other sources:

a)Airplane wings must be designed to ensure that air molecules are deflected downward after hitting the wing. 
b) Airplane wings must be designed to ensure that air molecules are deflected upward after hitting the wing. 
c) Airplane wings must be designed to ensure that air molecules move more rapidly past the bottom surface of the wing, creating a region of higher pressure. 
d) Airplane wings must be designed to ensure that air molecules move more rapidly over the top surface of the wing, creating a region of lower pressure. 
e) Airplane wings must be designed so that they are thick enough to ensure a significant pressure difference between the top and bottom surfaces of the wings.

The answer is D. I hope it helps.