HIV is (c) a viral disease. HIV, or Human Immunodeficiency Virus, is a lentivirus that attacks the immune system. It specifically targets CD4 cells, a type of T cell crucial for the body’s immune response. HIV weakens the immune system over time, making the body vulnerable to opportunistic infections and cancers. If left untreated, HIV can progress to AIDS (Acquired Immunodeficiency Syndrome), the advanced stage of the disease characterized by severe immune deficiency and opportunistic infections. HIV is primarily transmitted through unprotected sexual contact, sharing of contaminated needles, or from mother to child during childbirth or breastfeeding.