Which of the following is not an autoimmune disease?

The correct option is D Alzheimer's disease
Alzheimer is caused by the death of brain cells.it is a disorder which is neurodegenerative. There is progressive death of brain cells which occurs over time.
Rheumatoid arthritis is an autoimmune disease. It causes inflammation, swelling, and pain in and around the joints and can affect other body organs.
Psoriasis is autoimmune disease, it is a skin disease that causes red, itchy scaly patches.
Vitiligo is autoimmune disease, caused by the lack of a pigment called melanin in the skin.
So, the correct answer is- option a.