Q21 - Efficiency and redundancy are contradictory

[sarahbbright]

I got e not c. Thank you, Lord! It is because completely redundant (all letters) could be used in all words at least once...(and make sense, theoretically). Did anyone else have the "redundancy mis-understanding" I guess I missed this question due to? If I knew this I would not have needed to check D or E. Wish me good luck ?

[maryadkins]

This is an inference question. What can we figure out based on what we've been told?

(A) isn't supported because we know they can be used together to achieve both usefulness and reliability, but nowhere were we told that efficiency is what makes language useful and redundancy is what makes it reliable.

(B) is unsupported because we don't know if that's true.

(C) is also unsupported because while we are told what would happen if a language were completely efficient, we weren't told what would happen if a language were completely redundant. We don't know.

(D) is unsupported because it's reversed logic. We're told that if the human auditory system is imperfect --> not every permutation is an understandable word. But this doesn't mean that if it were perfect --> every permutation would be understandable. This answer choice negates both sides of the conditional without flipping them.

(E) is true. We were told:

If human auditory imperfect --> not every permutation is understandable word.

And we were also told that:

Completely efficient --> every permutation is an understandable word.

That means:

If human auditory imperfect --> every permutation is not understandable word --> not completely efficient.

That's answer choice (E).