Sentence 1 (BF1):
During landing, navigation systems receive radio signals from the airport to guide the plane to the runway.This is a fact.
Sentence 2:
Recently, one plane with low-power circuitry veered off course during landing, its dials dimming, when a passenger turned on a laptop computer.
This is evidence.
Sentence 3 (BF2) :
Clearly, modern aircraft navigation systems are being put at risk by the electronic devices that passengers carry on board, such as cassette players and laptop computers.This is the argument. This is also the conclusion.
Why does the author think that modern navigation systems are put at risk by electronic devices?
1. Because they are more susceptible to interference.
AND2. Because there is evidence that one aircraft (with modern navigation) veered off course when a laptop was turned on. (= Sentence 2)
Please note that both the reasons are needed to draw the conclusion - not just one of the above.
(A) The first is a principle that the argument relies on and the second is a conclusion that can be drawn from the first.The first is a fact that the argument relies on.
The second is a conclusion. However, the conclusion is not drawn from the first Boldface.
(B) The first is a fact that argument relies on and the second is a conclusion that must be drawn from this argument.The first is a fact that the argument relies on.
The second is a conclusion. However, the conclusion is not drawn from the argument.
(C) The first acknowledges a consideration that supports that main position; the second is that conclusion.Both parts of the above answer choice are true.
(D) The first is an evidence that supports the conclusion, the second is that conclusion.The first is not evidence.
The second is the conclusion.
(E) The first is a principle that is necessary for this argument, the second is a conclusion that could be drawn from this argument.The first is necessary for this argument.
The second is a conclusion. However, it cannot be drawn from the first.