Peter is in Professor 1's statistics course and he got a 95 on the first exam.

Mary is in Professor 2's statistics course and she got a 90 on her first exam.

If the mean onprofessor 1's test was an 85 and the mean on professor 2's test was an 80, then which of these two students can say they did the best on the exam compared to the rest of their class.

A. Peter, because he scored higher than Mary.

B. Mary, because her test was harder.

C. Both did equally well, because they both scored 10 points above the mean.

D. It is impossible to answer without knowing the variability of scores on each test.