The hairs of the shaving brush stick together when taken out of water. The reason for this is

The hairs of the shaving brush stick together when taken out of water primarily due to surface tension; option [A]. Surface tension arises from cohesive forces between water molecules, causing them to attract each other. When the shaving brush is submerged in water, water molecules adhere to the hairs and create a thin film on their surface. Upon removal from water, the cohesive forces between the water molecules cause them to cling together, resulting in the hairs sticking together.
While viscosity, elasticity, and friction play roles in various phenomena, they are not the primary reasons for the hairs of the shaving brush sticking together. Viscosity refers to a fluid’s resistance to flow and does not directly affect the hairs of the brush. Elasticity pertains to the ability of a material to return to its original shape after deformation and is not relevant to the sticking of the hairs. Friction is the resistance encountered when one object slides over another, but it is not the dominant factor in this scenario.

Understanding the role of surface tension elucidates why the hairs of the shaving brush tend to stick together when removed from water, a phenomenon commonly observed in daily grooming routines.