How many types of thermometers are listed?

• A. 2
• B. 3
• C. 4
• D. 5

Answer: (B)

Counting the distinct thermometer types listed is the key idea. You scan the list and identify each unique category, treating any repeats or overlaps as a single type. In this case, three different thermometer categories are named, so the total is three. For context, common categories you might see are digital/electronic thermometers, infrared thermometers, and traditional liquid-in-glass thermometers. If multiple entries refer to the same category, they don’t add to the count. So, the correct count is three.