**Core Concept**
Class II of HIV-associated diseases refers to the opportunistic infections that occur in the early stages of HIV infection, typically when the CD4 count is above 200 cells/μL. These infections often present with symptoms and can be treated with antiretroviral therapy and/or antimicrobial agents.

**Why the Correct Answer is Right**
Class II diseases include conditions such as oral candidiasis, esophageal candidiasis, and pulmonary tuberculosis. These infections often result from the reactivation of latent pathogens, such as Candida albicans, or the reactivation of Mycobacterium tuberculosis, which becomes more virulent as the immune system weakens. The CD4 count is a critical factor in determining the risk of developing these opportunistic infections.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a correct description of Class II HIV-associated diseases.
**Option B:** This option is not accurate, as it does not describe a characteristic feature of Class II HIV-associated diseases.
**Option C:** This option is incorrect, as it describes a condition that typically occurs in later stages of HIV infection, when the CD4 count is below 200 cells/μL.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the classification of HIV-associated diseases is based on the CD4 count, and understanding this relationship is crucial for diagnosing and treating opportunistic infections in HIV-positive patients.

**Correct Answer:** D.