The correct answer is (a) Protoplasm
The explanation is: Protoplasm of the cell is a fluid, similar to water, contains all the molecules in it. Cytoplasm contains all the particles inside the membrane of a cell. Cytosol is a part of cytoplasm possessing all the organelles excluding the cell nucleus. Matrix is a fluid present in different types depending upon the type of specialized structure such as stroma is the matrix of chloroplast.