Hint: Antigen is a toxic or foreign substance which induces an immune response in the body, especially the production of antibodies. A protective protein produced by the immune system in response to foreign substances, called the antigen, is also called immunoglobulin. Antibody is also called antigen. There would be interaction in the antigen and antibody present in the body.
Complete answer: Option A angiology: Circular lymph system studies are Angiology, i.e., arteries, venous, lymph vases, and conditions. It is a branch of science that studies the blood and lymph vessels and their disorder. Option A is incorrect. Option B cryobiology: Cryobiology is the branch of biology that affects low temperature on living organisms and death. The main focus of cryobiology is on the living organisms. But often it deals with the non-living organisms like machinery and other metal objects. Option B is incorrect. Option C Serology: Serology is the study of blood and body fluids. Especially the interaction of antigen and antibodies. In other words, it is a scientific or diagnostic examination of blood serum especially with regards to the response of the immune system to pathogens or introduced substances. So, option C is correct. Option D Haematology: Hematology is the branch of medicine involving study and treatment of blood. The diseases of the blood and bone mark and the immunological, welkin and vascular systems are diagnosed, treated and prevented. The science of hematology deeply affects the comprehension of many diseases because of the nature of the blood.
So, option C is the correct answer.
Note: Antigen and antibody are the foreign particles that are present in the blood. It is one of the body fluids. So, the study of interaction of antigen and antibodies in the blood is called serology. Serological test is called a serology test or antibody test. This term serology is referring to the diagnostic identification of antibody in the blood.