The nature of bonding forces in adsorption
(1) purely physical as Vander Waal's forces
(2) purely chemical
(3) both chemical and physical always
(4) none of these

The exact nature of bond will depend on the species involved....Physiosorption would occur by Van Der Waals forces , Chemisorption by chemical bond formation and some may occur due to electrostatic attraction. As in option C it's given it would chemical and physical always : it's the wrong option The correct option is : option D