Most serious form of AIDS is called …………………………….. .

Explanation

**Step-by-Step Text Solution:**

1. **Understanding AIDS**: AIDS stands for Acquired Immunodeficiency Syndrome. It is a serious condition caused by the Human Immunodeficiency Virus (HIV), which attacks the immune system.

2. **Identifying the Most Serious Form of AIDS**: The question asks for the most serious form of AIDS. In the context of AIDS, the term used to describe a severe manifestation of the disease is important.

3. **Defining AIDS Related Complex (ARC)**: The most serious form of AIDS is referred to as AIDS Related Complex (ARC). This term was commonly used during the early years of the AIDS epidemic.

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