Lupus, a condition in which the body attacks its own cells, is an example of
1-an allergic disorder.
2-an immunodeficiency disorder.
3-a cancer of the immune system.
4-an autoimmune disorder.

Option 4, an autoimmune disorder, is the correct answer.

Explanation:

An autoimmune disorder can be described as a disorder in which the immune cells of a body attack the own cells of a body.

Lupus can be described as an autoimmune disease which is long termed. In this disorder, a person's immune system attacks its own healthy cells. The immune system is unable to differentiate between the pathogenic cells and the healthy cells of the body. As a result, tissue damage is caused.