Temperature profile near the surface of a convectively cooled flat plate - GATE ME '14 S1

The non-dimensional fluid temperature profile near the surface of a convectively cooled flat plate is given by (Tw−T)/(Tw−T∞) = a+b(y/L)+c(y/L)^2, where y is measured perpendicular to the plate, L is the length, and a,b and c are arbitrary constants. Tw and T∞ are wall and ambiyent temperatures, respectively. If the thermal conductivity of the fluid is k and the wall heat flux is q″, the Nusselt number Nu = q″(L/k)/(Tw−T∞) is equal to A. a B. b C. 2c D. (b+2c)