In a two dimensional incompressible steady flow around an airfoil, the stream lines are 2 cm apart at a great distance from the airfoil, where the velocity is 30 m/sec. The velocity near the airfoil, where the stream lines are 1.5 cm apart, is

a) 22.5 m/sec.
b) 33 m/sec.
c) 40 m/sec.
d) 90 m/sec.
Ans: c