Answer & Explanation
Auto-immune disease :: Sometimes, due to genetic and other unknown reasons, the body attack self-cells. This results in damage to the body and is called auto-immune disease.
From the options,
-> Rheumatoid arthritis is an autoimmune disorder in which antibodies are produced against the synovial membrane and cartilage.
-> Vitiligo causes white patches on skin also characterised as autoimmune disorder.
-> Psoriasis is a skin disease that causes itchy or sore patches of thick red skin and is also autoimmune.
-> Alzheimer's disease is a chronic neurodegenerative disease. Alzheimer's disease is due to deficiency of neurotransmitter acetylcholine.
Hence, Alzheimer's is not the auto-immune disease.