ANS:C - surface tension

Falling drops of water become spheres primarily due to surface tension. Surface tension is the property of a liquid's surface that allows it to resist external forces. When water falls in droplets, surface tension acts to minimize the surface area of the droplet. A sphere has the minimum surface area for a given volume, so the water naturally forms into spherical shapes due to the surface tension. While cohesion and adhesion play roles in the behavior of water molecules, surface tension is the primary force responsible for the spherical shape of water droplets. Cohesion refers to the attraction between molecules of the same substance (water molecules attracting each other), while adhesion refers to the attraction between molecules of different substances (water molecules attracted to the surface they are in contact with). These forces contribute to the behavior of liquids but do not directly lead to the spherical shape of water droplets. Therefore, falling drops of water become spheres primarily due to surface tension.