The correct option is C Emulsion
The colloidal systems where:
a. Dispersed phase is a solid and the dispersion medium is a gas, are known as aerosol.
b. Dispersed phase is a gas and the dispersion medium is a liquid, is known as foam.
c. Both the dispersed phase and the dispersion medium are liquids, are known as emulsions.
d. Dispersed phase is a liquid and the dispersion medium is a solid, is known as a gel.