Final answer:
The correct answer is a. P(MS).
Step-by-step explanation:
The correct answer is a. P(MS).
In this context, P(MS) represents the probability that a randomly chosen student studies every day, given that the student passes a math test. It combines the probabilities of both events M and S. Option b, P(M AND S), represents the probability that a randomly chosen student both passes a math test and studies every day, which is not what the question is asking for.