Which of the following formulation strategies will increase the viscosity of a shampoo? (More than one correct answer)

Group of answer choices

1. Increase the concentration of surfactant.

2. Addition of electrolyte to the aqueous phase to alter surfactant micellar structure from spherical to cylindrical.

3. Use of several surfactants such as an anionic primary surfactant and amphoteric secondary surfactant to alter surfactant micellar structure from spherical to cylindrical.

4. Addition of water soluble polymers.