Drag force is a function of i) projected area of the body ii) mass density of the fluid iii) velocity of the body The correct answer is A. (i) and (ii) B. (i) and (iii) C. (ii) and (iii) D. (i), (ii) and (iii)

The correct answer is D. (i), (ii) and (iii).

Drag force is a force that opposes the motion of an object through a fluid. It is caused by the interaction of the fluid molecules with the surface of the object. The drag force is proportional to the projected area of the object, the mass density of the fluid, and the square of the velocity of the object.

The projected area is the area of the object that is facing the oncoming fluid. The mass density of the fluid is the mass of the fluid per unit volume. The velocity of the object is the speed of the object relative to the fluid.

The drag force is a vector quantity, which means that it has both magnitude and direction. The direction of the drag force is opposite to the direction of the motion of the object.

The drag force is a major factor in the design of vehicles and other objects that move through fluids. For example, the drag force is a major factor in the design of airplanes and cars. The drag force can be reduced by streamlining the shape of the object, by reducing the mass density of the fluid, or by reducing the velocity of the object.