Final answer:
The Measles virus (option B) is the correct answer as it can be transmitted via airborne droplets and direct contact, and it can cause both pneumonia and encephalitis.
Step-by-step explanation:
The question involves identifying an airborne and direct contact virus that can cause pneumonia and encephalitis. Among the options provided, the Measles virus (B) is known for being highly contagious and can be transmitted through the air by breathing, coughing, or sneezing, and it has the potential to cause pneumonia. Measles virus can also cause encephalitis in some cases. In comparison, the Influenza virus primarily causes respiratory infections and can lead to pneumonia but is generally not associated with encephalitis. The Herpes simplex virus is known to cause encephalitis but is not primarily associated with pneumonia. The Varicella-zoster virus, which causes chickenpox and shingles, can lead to pneumonia, especially in adults, but encephalitis is a rare complication.
In conclusion, the correct answer is B. Measles virus, as it can cause both pneumonia and encephalitis and is spread through airborne transmission and direct contact.