**Core Concept**
The picornavirus group is a family of small, non-enveloped RNA viruses that include various pathogens responsible for common illnesses such as the common cold, poliomyelitis, and hand-foot-and-mouth disease. These viruses have a single-stranded RNA genome and are typically transmitted through the fecal-oral route or respiratory droplets.

**Why the Correct Answer is Right**
The picornavirus group includes viruses such as poliovirus, coxsackievirus, echovirus, and enterovirus, which are known for their ability to cause a range of diseases. These viruses are able to replicate in the gastrointestinal tract and can be spread through contaminated food and water or by direct contact with an infected individual. The replication of picornaviruses involves the translation of the viral RNA into a protein that acts as a replicase, which then produces new viral RNA and proteins.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not specified which virus is being tested.
**Option B:** This option is incorrect because it is not specified which virus is being tested.
**Option C:** This option is incorrect because it is not specified which virus is being tested.

**Clinical Pearl / High-Yield Fact**
One key feature of picornaviruses is their ability to cause a range of diseases, from mild respiratory illnesses to severe neurological disorders. The poliovirus, for example, can cause paralytic poliomyelitis, a disease characterized by muscle weakness and paralysis.

**Correct Answer: A. All are included in picorna group of viruses except -**