This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
[{'content': "All of the following forces are involved in Antigen antibody reaction except - \nSelect and explain. \nA. Vander Waal's forces, B. Electrostatic bond, C. Hydrogen bond, D. Covalent bond", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Antigens are bound to antibodies through weak and noncovalent interactions such as electrostatic interactions, hydrogen bonds, Van der Waals forces, and hydrophobic interactions. Ref: Ananthanarayan & Panikers textbook of microbiology 9th edition pg:103', 'role': 'assistant'}]