Arrange the parts to form a correct sentence: (1) He entered the meeting link. (2) The audio started breaking. (3) The session had already started. (4) He messaged the coordinator at once.

Explanation

The correct option is (a). To form a meaningful and grammatically correct sequence, we must arrange the events in a logical time order. Sentence (1) should come first because it introduces the initial action: he joined the meeting by entering the link. Sentence (3) logically follows because after joining, he realizes the session had already started. This is a natural observation immediately after entering. Sentence (2) comes next because during an ongoing session, a technical issue (audio breaking) can occur after joining. Sentence (4) must be the last because the message to the coordinator is a reaction to the problem (audio breaking) and the urgent situation. Thus, the coherent sentence flow is: joining the meeting, noticing it has started, facing audio issues, and then informing the coordinator. So the correct answer is (a)