A Student Studying for a Vocabulary Test Knows the Meanings

A student studying for a vocabulary test knows the meanings of 13 words from a list of 20 words. If the test contains 9 words from the study list, what is the probability that at least 7 of the words on the test are words that the student knows?

A) 0.971
B) 0.094
C) 0.858
D) 0.182
E) 0.272
F) 0.402