Correct Answer: B
Explanation:
Always check pronouns first. We cannot use ‘their’ when referring to a school. So we can eliminate A and D. Next we need the adverb ‘extraordinarily’ not the adjective ‘extraordinary’ to modify ‘high’, and so we eliminate C.
Of the remaining options, E is wordy and also has a verb-subject agreement problem: a percentage of students should be treated as plural and so we need ‘fail’. Hence the answer is B.