air flowing

We have air flowing over a smooth flat plate. The air is at T = 300 C and p = 1.01 atm. The flowrate is 8.5 m/s over the plate, giving laminar flow. What is the thickness of the boundary layer 0.30 m from the leading edge of the plate? a) 1.36 m b) 51.8 mm c) 0.071 mm d) 3.72 mm e) 28.6 cm