Answer:
b. Auto-immune diseases
Step-by-step explanation:
Auto-immune disease occurs when the immune system mistakenly attacks the body cells.
The major histocompatibility complex(MHC) is a large locus on vertebrate's DNA containing a set of closely linked polymorphic genes that code for cell surface proteins essential for the adaptive immune system. It was discovered in the study of tissue compatibility during transplantation.
Failure of your immune cells to recognize MHC proteins on your normal body cells might result in auto-immune disease.