**Core Concept**
Varicella, also known as chickenpox, is a highly infectious illness caused by the **varicella-zoster virus**. This infection primarily affects children and is characterized by a distinctive rash and fever. The virus can reactivate later in life to cause **herpes zoster**, or shingles.

**Why the Correct Answer is Right**
Without the specific options provided, the general approach to varicella infection involves understanding its transmission, symptoms, and complications. Varicella-zoster virus infects individuals through respiratory droplets or direct contact with rash lesions, leading to symptoms such as a pruritic vesicular rash, fever, and malaise.

**Why Each Wrong Option is Incorrect**
**Option A:** Would be incorrect if it stated something universally true about varicella.
**Option B:** Similarly, if it mentioned a common symptom or transmission method, it would be incorrect as the statement to be identified is "not true."
**Option C:** This option would be wrong if it discussed a known complication or a fact about the varicella-zoster virus.
**Option D:** If this option mentioned the virus's reactivation as herpes zoster, it would also be an incorrect choice for "not true."

**Clinical Pearl / High-Yield Fact**
A key point to remember is that varicella infection can lead to severe complications in immunocompromised individuals and pregnant women, making vaccination and preventive measures crucial.

**Correct Answer:** D. Varicella is not a bacterium.