Correct Answer: D
Explanation:
| ANEMOMETER: | a gauge for determining the force or speed of the wind |
| Distance: | the extent or amount of space between two things, points |
| Altitude: | height; esp., the height of a thing above the earth‘s surface or above sea level a high place or region |
| Smog: | smoke or other atmospheric pollutants combined with fog in an unhealthy or irritating mixture |