Final answer:
Cassio doesn't want to drink with Iago during the celebrations on Cyprus in Othello because he cannot trust Iago, Montano will be watching him, and he knows he cannot handle alcohol well. Option 3.
Step-by-step explanation:
In the play Othello, Cassio does not want to drink with Iago during the celebrations on Cyprus for multiple reasons. Firstly, he knows he cannot trust Iago, as Iago has shown himself to be deceitful and manipulative throughout the play. Secondly, Cassio is aware that Montano will be present and watching him.
Cassio wants to uphold a professional and responsible image, as Montano reports directly to Othello. Lastly, Cassio may also be aware of his own alcohol tolerance and knows that he cannot handle alcohol well.
So Option 3