HIV primarily targets and infects CD4+ T cells (also known as T4 lymphocytes), which are a type of white blood cell important for the immune system's functioning. As HIV infects and destroys CD4+ T cells, it weakens the immune system, making the individual susceptible to various opportunistic infections and illnesses, leading to the development of AIDS when the immune system is severely compromised.
So, the correct option is (C): T4 lymphocytes