Hi Principessa227!
You're on the right track when it comes to looking for an answer choice that helps show the radar system did not cause any other issues on the flight! In fact, that's exactly what answer choice (A) does. How? Well, let's break down the argument!
The author in this stimulus concludes that passengers on planes with the system are safer than those on airplanes without the system. In order to show this, they rely on a few key pieces of evidence:
Collision-avoidance radar systems exist
These systems provide pilots with information about the proximity of other planes
The system warns pilots to take evasive action
But wait... at the very end of the stimulus, the author says that the system "frequently warns pilots to evade phantom airplanes." Interesting! This is a curious caveat to add to an argument, it makes one wonder if frequently warning pilots to evade phantom airplanes might be a bad thing? So, a good prephrase to strengthen this argument is to show that this is not a safety hazard!
Turning now to the answer choices, we can see that (A) is very appealing. If evasive action in response to the warnings pose no risk to passengers, this makes it okay that pilots are avoiding phantom airplanes! Better safe than sorry, right?
Looking at answer choice (B), we see that commercial airplanes are in greater danger of colliding with other airplanes while on the ground than in flight. If commercial airplanes are in greater danger of colliding on the ground rather than in flight, does this make it more likely that passengers really are safer on airplanes equipped with the system? Does this information show the radar system isn't causing any issues in flights? Not really, (B) seems to be somewhat extraneous information. (B) can be eliminated.
Turning to (C), we are informed that commercial airplanes are rarely involved in collisions while in flight. But what are we supposed to do with this information? In what way does this eliminate the risk or improve the safety? Realistically, all this answer choice does is tell us that collisions while in flight are rare to begin with, but nothing about whether or not the radar system improves the safety or not. Think about it this way: let's say that all commercial airplanes, on average, only get into 2 collisions every year despite flying thousands of times. But, airplanes with the new system only get into 1 collision every year despite flying thousands of times. Now, that would certainly help strengthen the argument. But, what if, instead, airplanes with the new system now get into 3 collisions every year? That would weaken the argument. Ultimately, we just don't know how this would impact the argument, since all (C) does is establish that collisions in the air are rare.
(D) and (E) can be eliminated for similar reasons, the facts contained within those answer choices are ultimately unimpactful for the argument presented in the stimulus.
Thus, we can see that (A) is the correct answer because it eliminates the possibility of harm arising from evasive actions (even in response to phantom airplanes)!
I hope this helps
Kate
