Answer:
Step 1: Determine which options are correct
What will the economy be like in the future?
- Option A: too broad
How can virtual reality be used in health care?
- Option C: effective
How many gallons of water will we use in 2025?
- Option B: too narrow
What are the best strategies for increasing food production in the future?
- Option C: effective
For the first question, the reason why it is too broad is because the economy in the future is a huge topic. It will not be able to be covered in one topic. In questions two, the reason why the answer is effective is because this is a specified research question in a wide category. For the third question, the answer is too narrow because there is really no use of knowing how much gallons of water we will use in 2025. Finally, in the fourth question the answer is effective because it is a specified research question in a specific topic/category.
See the attachment for clarification