A surfactant molecule has a hydrophilic head and a hydrophobic tail. In a shampoo, the tail's primary function is to:

Explanation

Surfactants reduce the surface tension of water and form micelles in which the hydrophobic tails point inward and grab onto oil and dirt, while the hydrophilic heads point outward into the water. Rinsing then sweeps the entire micelle, oil included, off the hair. Cal/OSHA's Hazard Communication Standard §5194 requires that the SDS for shampoos disclose surfactant identity and hazards. Option A describes a conditioner's positively charged quaternary, not a shampoo surfactant. Option B is unrelated; surfactants are not pH adjusters. Option C imagines transdermal delivery into the cortex, which surfactants do not perform during a normal shampoo.