Final answer:
Iago tells Montano that Cassio is plotting to murder Othello.
Step-by-step explanation:
Iago tells Montano that Cassio is plotting to murder Othello.
In the play Othello by William Shakespeare, Iago manipulates and deceives various characters, including Montano, in order to achieve his own malicious goals. Iago fabricates a lie about Cassio intending to kill Othello, which fuels Montano's concern and distrust towards Cassio.
This lie creates a rift between Montano and Cassio and contributes to the downfall of the characters in the play.