**Core Concept**
Herpangina is a self-limiting viral illness characterized by the development of small, painful ulcers on the tonsils and the back of the throat. The condition is caused by specific viruses that lead to the formation of these ulcers.

**Why the Correct Answer is Right**
Herpangina is primarily caused by coxsackieviruses A and B, which belong to the Picornaviridae family. These viruses infect the epithelial cells of the tonsils and the throat, leading to the formation of small, vesicular lesions that eventually rupture to form ulcers. The coxsackieviruses are highly contagious and spread through direct contact with an infected person or through contaminated food and water.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because coxsackieviruses are the primary cause of herpangina, not echoviruses.
**Option B:** This option is incorrect because influenza viruses are associated with respiratory infections, not herpangina.
**Option C:** This option is incorrect because herpes simplex virus (HSV) causes cold sores and genital herpes, not herpangina.

**Clinical Pearl / High-Yield Fact**
To distinguish herpangina from other viral illnesses, look for the characteristic small, painful ulcers on the tonsils and the back of the throat. Herpangina is often associated with fever, sore throat, and swollen lymph nodes.

**Correct Answer:** D. Coxsackieviruses A and B.