The weight of an aeroplane flying in air is balanced by

• A

  Upthrust of the air which will be equal to the weight of the air having the same volume as the plane

• B

  Force due to the pressure difference between the upper and lower surfaces of the wings, created by different air speeds on the surface

• C

  Vertical component of the thrust created by air currents striking the lower surface of the wings

• D

  Force due to the reaction of gases ejected by the revolving propeller