The 3D flow characteristic attributed to the wings is a by-product of_____

A)
Extra lift produced
B)
Thickness of the wing
C)
Pressure imbalance over top and bottom surfaces of the wing
D)
Pressure imbalance between leading and trailing edge of the airfoil

Correct Answer :   Pressure imbalance over top and bottom surfaces of the wing


Explanation : Lift over an airfoil is produced by the pressure difference over top and bottom surfaces of airfoil. But for the finite wings, this creates a by-product in the form of span-wise flow, which gives a 3D flow. Thickness of the wing and extra lift produced are vague options.