(a) You and a randomly selected student from your class both earn A's in this course.
Answer: Here selection of one student is independent of the other.
Therefore it is independent.
(b) You and your class partner both earn A's in this course.
Answer: Here enough data is not available to comment whether the given event is mutually exclusive or independent.
Therefore it is neither.
(c) If two events can occur at the same time, they must be independent.
Answer: If both the events occur at the same time then it is not necessary they are independent.
Therefore it is False.