**Core Concept**
Human immunodeficiency virus (HIV) is a lentivirus that primarily targets and infects CD4+ T lymphocytes, also known as T helper cells, which play a crucial role in the adaptive immune system. HIV infection leads to the depletion of these cells, severely compromising the body's ability to fight off opportunistic infections and cancer.

**Why the Correct Answer is Right**
The correct answer is related to the mechanism of HIV infection. HIV enters the host cell by binding to the CD4 receptor and a co-receptor, typically CCR5 or CXCR4, on the surface of CD4+ T cells. Once inside the cell, the virus integrates its genetic material into the host cell's DNA, leading to the production of new viral particles and the destruction of the host cell. This process is repeated continuously, resulting in the gradual decline of CD4+ T cells and the progression of HIV infection.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect, as HIV primarily targets CD4+ T cells.
**Option B:** Incorrect, as while HIV can also infect other cells such as macrophages and dendritic cells, CD4+ T cells are its primary target.
**Option C:** Incorrect, as HIV does not primarily target B cells.

**Clinical Pearl / High-Yield Fact**
A key aspect of HIV treatment is the use of antiretroviral therapy (ART), which aims to suppress viral replication and restore CD4+ T cell counts. Early initiation of ART is crucial in preventing the progression of HIV to acquired immunodeficiency syndrome (AIDS).

**Correct Answer:** B.