Pandemic are caused by -a) Hepatitis Bb) Influenza-Ac) Influenza-Bd) Influenza-Ce) Cholera

**Core Concept**
Pandemics are large-scale epidemics that affect a significant portion of a population, often worldwide. They are typically caused by highly contagious and virulent pathogens that can spread rapidly due to factors like global travel and connectivity.

**Why the Correct Answer is Right**
Influenza A viruses are responsible for some of the most devastating pandemics in human history, such as the 1918 Spanish flu pandemic, which killed an estimated 50 million people. This is because Influenza A viruses have a high mutation rate, which allows them to rapidly change their surface proteins and evade the immune system, making them highly contagious and virulent. Additionally, Influenza A viruses can be transmitted from animals to humans (zoonotic transmission), which can lead to the emergence of new strains.

**Why Each Wrong Option is Incorrect**
* **Option A:** Hepatitis B is a major public health concern, but it is not typically associated with pandemics. Hepatitis B is usually spread through bodily fluids, and while it can cause severe liver disease, it does not have the same level of contagiousness as Influenza A.
* **Option B:** Influenza A and Influenza B are both types of influenza viruses, but Influenza B is generally less severe and not typically associated with pandemics.
* **Option C:** While Influenza B can cause outbreaks, it is not as contagious or virulent as Influenza A, and is therefore less likely to cause a pandemic.
* **Option D:** Cholera is a bacterial infection caused by Vibrio cholerae, which is typically spread through contaminated water or food. While cholera can cause outbreaks, it is not typically associated with pandemics.

**Clinical Pearl / High-Yield Fact**
Remember that Influenza A viruses are the primary cause of pandemics, and their high mutation rate and zoonotic transmission make them a significant public health concern.

**Correct Answer:** C. Influenza-B