How does vaccination with a weakened varicella virus (chicken pox) help us to avoid contracting chicken pox?

• A. The introduced, weakened virus can compete with another chickenpox virus in terms of nutrients.
• B. The introduced virus can cause the weakening of the incoming chickenpox virus.
• C. The weakened virus can produce enzymes that can degrade another chickenpox virus.
• D. The weakened virus can stimulate the immune system to produce antibodies.

Answer: (D)