Which of the following activities is most likely to result in an external benefit?

• A. Getting vaccinated against a contagious disease
• B. Dumping waste into a river
• C. Smoking cigarettes in a public park
• D. Driving a car during rush hour

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the concept of externalities. Externalities occur when a person's actions have effects on third parties that are not reflected in market prices. These can be either external costs (negative externalities) or external benefits (positive externalities).
2. Step 2: Identify the nature of each activity in terms of externalities. For example, dumping waste into a river typically imposes costs on others (negative externality), while smoking in a public park can harm others through secondhand smoke (negative externality).
3. Step 3: Analyze the activity of getting vaccinated against a contagious disease. This action not only protects the individual but also reduces the likelihood of spreading the disease to others, thereby providing a positive external effect on public health.
4. Step 4: Compare the activities to determine which one provides a positive externality. The activity that benefits others beyond the individual engaging in it is the one with an external benefit.
5. Step 5: Conclude that getting vaccinated is most likely to result in an external benefit because it helps prevent disease transmission, benefiting society as a whole.