Concept:The underlined expression describes the violent fight that Othello interrupts.Explanation:Othello hears a disturbance and angrily calls it a “barbarous brawl.”He demands to know who started this uproar and questions Iago about it.The disturbance was caused by Cassio, who had been provoked by Roderigo, stabbing and wounding Montano.Therefore, the expression refers to that violent incident.Answer:D. Stabbing of Montano by Cassio