Considering the given discrete distribution, it is found that the probability that a randomly selected student earned a C or better is of 0.91.
It gives the probability of each grade, as follows:
Hence, the probability of a grade of C or better is given by:
[tex]P(X \geq C) = P(X = A) + P(X = B) + P(X = C) = 0.43 + 0.31 + 0.17 = 0.91[/tex]
More can be learned about discrete probability distributions at https://brainly.com/question/24802582
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