Final answer:
A person may undergo chemotherapy or have HIV infection in cases of cancer (for chemotherapy) or HIV (also potentially involving chemotherapy if related cancer occurs). A patient with a CD4 T-cell count of 700/μL without illness is in the early stages of HIV infection, not yet progressing to AIDS. The correct option is 3.
Step-by-step explanation:
The conditions in which a person may undergo chemotherapy or have HIV infection include both cancer and HIV. Chemotherapy is a treatment most commonly used for cancer, but can also be part of the treatment for HIV-infected patients in certain cases.
A patient with cancer may undergo chemotherapy to kill or slow the growth of cancer cells. A person with HIV infection might receive chemotherapy if they develop certain HIV-related cancers, such as Kaposi's sarcoma, that can arise as the immune system becomes weakened.
The stage of an HIV infection is categorized based on CD4 T-cell counts and the presence or absence of certain diseases. A patient with a CD4 T-cell count of 700/μL and no apparent illness is in the early stages of HIV infection, which is not AIDS (stage 3 is AIDS, characterized by a CD4 count below 200 cells/µL or opportunistic diseases).
If the HIV infection is not treated, the person may eventually progress to AIDS, where the immune system is severely compromised, leading to opportunistic diseases that are typically the immediate cause of death.