Concept:Othello speaks these lines after the storm destroys the Turkish fleet that was about to attack Cyprus.
Explanation:The "tempest" is the violent sea storm that had endangered the ships.
The same storm destroyed the Turkish warships, so the planned attack on Cyprus fails.
Thus, the threat of war is over and Othello arrives safely on the island.
He is overjoyed because he is reunited with Desdemona.
The "calms" that follow the "tempest" stand for peace and happiness after danger.
Othello says he is so content that if he died at that moment, he would still be most happy.
This speech is therefore occasioned by the defeat of the Turks, not by a departure or a mere return.
Answer:D. the defeat of the Turks.