Professor Woo Noticed That the Distribution of Students' Scores on Her

Professor Woo noticed that the distribution of students' scores on her last biology test had an extremely small standard deviation. This indicates that the

A) test was given to a very small class of students.
B) test was a poor measure of the students' knowledge.
C) students generally performed very well on the test.
D) students' scores tended to be very similar to one another.