AIDS, or Acquired Immunodeficiency Syndrome, is characterized by a number of symptoms such as swollen lymph nodes, night sweats, loss of memory, and loss of weight.

Swollen lymph nodes occur as the body tries to fight off the HIV infection. Night sweats are a typical symptom of many infections and are also common in AIDS patients. Memory loss can be caused by HIV-associated dementia or by opportunistic infections or tumors that affect the brain. The loss of weight, commonly called `AIDS wasting`, is a sign of advanced disease.

Thus, all four options listed, hence the correct answer is indeed option 4. It`s crucial to remember that while these symptoms can be associated with AIDS, they also occur in many other diseases. They alone do not confirm the disease, which would be diagnosed through a suitable HIV test.