Tumour cells have been shown to avoid detection and destruction by the immune system. Therefore the patients are given certain substances called biological response modifiers (BRM) which activates their immune system and helps in destroying the tumour. Identify the BRM.

The correct option is B Alpha interferon

Alpha interferon
Alpha interferon is a cytokine produced by white blood cells (except lymphocytes) in response to infections from pathogens including viruses. These interferons have anticancer properties and therefore are used in chemotherapy. Interferons act as biological response modifiers, stimulating the immune system to fight against the cancerous cells.

Alpha lactalbumin
Alpha lactalbumin is a protein that regulates lactose production in the milk of mammals.

Alpha-1 antitrypsin
Alpha-1-antitrypsin is produced by the liver. Lungs and liver tissues are protected from infections by this protein.

Gamma globulin
Gamma globulins or immunoglobulins or antibodies are serum proteins produced by B lymphocytes. They help in the defence of the body against pathogens.
Hence the correct option is (a).