## Core Concept
The question tests the knowledge of viral characteristics, specifically focusing on the type of genetic material, capsid symmetry, and presence or absence of a lipid envelope. Viruses can have DNA or RNA as their genetic material, their capsids can have helical or icosahedral symmetry, and some viruses are enveloped while others are not.

## Why the Correct Answer is Right
The correct answer, **B. Adenovirus**, possesses DNA as its genetic material. Adenoviruses have a capsid with icosahedral symmetry, which is composed of hexons and other proteins. Importantly, adenoviruses do not have a lipid envelope. This characteristic distinguishes them from viruses like herpesviruses, which are enveloped.

## Why Each Wrong Option is Incorrect
- **Option A: Herpesvirus** - Herpesviruses have DNA, but they also have a lipid envelope, which makes them incorrect for this question.
- **Option C: Poxvirus** - Poxviruses are unique because they have a complex structure that includes a lipid envelope and a large genome. They do not fit the description of having no lipid envelope.
- **Option D: Papovavirus** - This is an outdated term that was historically used to refer to viruses now classified as Papillomaviridae and Polyomaviridae. These viruses have DNA and icosahedral symmetry but the term is not commonly used and can be confusing. However, the more accurate and commonly used terms for viruses fitting the description given would directly point towards adenoviruses.

## Clinical Pearl / High-Yield Fact
A key point to remember is that **adenoviruses** are commonly associated with infections such as the common cold, conjunctivitis, and gastroenteritis. They are also used as vectors in vaccine development and gene therapy due to their ability to infect a wide range of cell types and their safety profile.

## Correct Answer: B. Adenovirus