The correct choice is (c) Ammonium sulphate removal by dialysis
Easy explanation: In the above diagram, enzyme solution has placed a bag of selectively permeable and this is immersed in a large volume of buffer which is stirred continuously. The procedure is carried out at 4 °C. This membrane allows small molecules ammonium and sulphate ions to pass into the buffer and equilibrate it. But this membrane does not allow the large weight molecular compounds like enzymes to pass through the membrane. Hence this diagram represents ammonium sulphate removal by dialysis. Ultrasonication and homogenization are used to extract enzyme from the cell by using physical forces. Ammonium sulphate fractionation is used to precipitate enzyme by using the salting out principle.