+113 The final mathematics exam at a certain school contains questions of equal difficulty and is matched to the students' past performance in mathematics. Four students who take the exam have averages 25%, 50%, 60%, and 80%. What is the probability that at least one of these students will get the first question on the exam correct?
A) 97/100
B) 9/10
C) 17/20
D) 13/15
E) 23/30
