Explanation

@mjenei, Happy to help. This is a tricky question. However, one thing that's important to note is that the meteorologist is counting on there being more tornadoes that are actually detected now. In the 1950s, it's likely that many of the really big ones were detected. Now, the meteorologist is suggesting that we are able to detect smaller, less noticeable tornadoes because we have better detection technologies. Thus, it'd be really helpful to know that the majority of the increase in the number of detected tornadoes came from smaller tornadoes or tornadoes that were in really rural areas. If any of the tornadoes that are now detected would likely have not been detected before, this would greatly help the meteorologist's argument. (C) says, "The number of large and medium sized tornadoes reported annually has remained roughly constant since the 1950s." (C) is tricky, but it actually helps the meteorologist's argument a lot. If the total number of medium and large sized tornadoes has remained the same, this suggests that the increase in reports has come from more detections of smaller tornadoes. Because the meteorologist says that we're now better at detecting tornadoes, it makes sense that we may have missed many tornadoes in the 1950s that we now are able to detect. This therefore helps the meteorologist's argument that the increase in reports of tornadoes does not mean that there has been an increase in the actual number of tornadoes. Thus, (C) is the correct answer choice. Hope this helps. Let us know if you have any more questions!

@Ravi: Looking back on this question, I can see how C could be a correct answer. However, reading through your explanation, I'm not sure where you got the information,"...In the 1950s, It's likely that many of the really big ones were detected. Now, the meteorologist is suggesting that we are able to detect smaller, less noticeable tornadoes..." I'm really confused about where this size information comes into the question body? The text didn't mention size so I didn't want to assume information from outside the stimulus and thus, rejected C.