Question: In Shakespeare's "Othello," Iago plotted to assassinate which person under Othello's command and failed?

Context paragraphs:
Michael Cassio: Michael Cassio, or simply Cassio, is a fictional character in William Shakespeare's "Othello".  The source of the character is the 1565 tale "Un Capitano Moro" by Cinthio; Cassio is unnamed in Cinthio but referred to as "the squadron leader".  In the play, Cassio is a young and handsome lieutenant under Othello's command who becomes one of Iago's several victims in a plot to ruin Othello.

Bianca (Othello): Bianca is a fictional character in William Shakespeare's "Othello" (c. 1601–1604).  She is Cassio's jealous lover.  Despite her brief appearance on stage, Bianca plays a significant role in the progress of Iago's scheme to incite Othello's jealousy of Cassio.  Bianca is traditionally regarded as a courtesan, although this occupation is not specifically designated in the drama.  The character was occasionally cut from performances in the 19th century on moral grounds.  Bianca is not to be confused with Bianca Minola in Shakespeare's "The Taming of the Shrew".

Desdemona: Desdemona is a character in William Shakespeare's play "Othello" (c. 1601–1604).  Shakespeare's Desdemona is a Venetian beauty who enrages and disappoints her father, a Venetian senator, when she elopes with Othello, a black man several years her senior.  When her husband is deployed to Cyprus in the service of the Republic of Venice, Desdemona accompanies him.  There, her husband is manipulated by his ensign Iago into believing she is an adulteress, and, in the last act, she is murdered by her estranged spouse.

Iago: Iago is a fictional character in Shakespeare's "Othello" (c. 1601–1604).  Iago is the play's main antagonist, and Othello's standard bearer.  He is the husband of Emilia, who is in turn the attendant of Othello's wife Desdemona.  Iago hates Othello and devises a plan to destroy him by making him believe that his wife is having an affair with his lieutenant, Michael Cassio.

Othello: Othello ("The Tragedy of Othello, the Moor of Venice)" is a tragedy by William Shakespeare, believed to have been written in 1603.  It is based on the story "Un Capitano Moro" ("A Moorish Captain") by Cinthio, a disciple of Boccaccio, first published in 1565.  The story revolves around its two central characters: Othello, a Moorish general in the Venetian army and his unfaithful ensign, Iago.  Given its varied and enduring themes of racism, love, jealousy, betrayal, revenge and repentance, "Othello" is still often performed in professional and community theatre alike, and has been the source for numerous operatic, film, and literary adaptations.

Othello (paintings): Othello is a series of paintings executed in 1985 by Nabil Kanso.  The subjects of the paintings are loosely based on Shakespeare’s tragedy Othello.  The series comprises 60 paintings dealing with themes of love, race, jealousy, betrayal, and evil.  They depict scenes embodying compositions of figural and metaphorical imagery that may be seen as visually reflecting the intimate and dramatic relationship between Othello and Desdemona, and the tense and uneasy relation that passes between and through Othello, Desdemona and Iago.

Roderigo: Roderigo is a fictional character in Shakespeare's "Othello" (c.1601-1604), where he serves as the secondary antagonist of the play.  He is a dissolute Venetian lusting after Othello's wife Desdemona.  Roderigo has opened his purse to Iago in the mistaken belief that Iago is using his money to pave the way to Desdemona's bed.  When the assassination of Michael Cassio runs amiss, Iago fatally wounds Roderigo.

Othello error: Othello error occurs when a suspicious observer discounts cues of truthfulness.  Essentially the Othello error occurs, Paul Ekman states, "when the lie catcher fails to consider that a truthful person who is under stress may appear to be lying" their non-verbal signals expressing their worry at the possibility of being disbelieved.  A lie-detector or polygraph may be deceived in the same way, by misinterpreting nervous signals from a truthful person.  The error is named after William Shakespeare's tragic play "Othello"; the dynamics between the two main characters, Othello and Desdemona are a particularly notable example of the error in practice.

Othello (1995 film): Othello is a 1995 film based on William Shakespeare's tragedy of the same name.  It was directed by Oliver Parker and stars Laurence Fishburne as Othello, Irène Jacob as Desdemona, and Kenneth Branagh as Iago.  This is the first cinematic reproduction of the play released by a major studio that casts an African American actor to play the role of Othello, although low-budget independent films of the play starring Ted Lange and Yaphet Kotto predated it.

Emilia (Othello): Emilia is a character in the tragedy "Othello" by William Shakespeare.  The character's origin is traced to the 1565 tale, "Un capitano Moro" from Giovanni Battista Giraldi Cinthio's "Gli Hecatommithi".  There, the character is described as young and virtuous, is referred to simply as the ensign's wife, and becomes Desdemona's companion in Cyprus.  In Shakespeare, she is named Emilia, is the wife of Othello's ensign, Iago, and is an attendant to Othello's wife, Desdemona.  While considered a minor character in the drama, she has been portrayed by several notable actresses on film, with Joyce Redman receiving an Academy Award nomination for her performance.

Supporting paragraphs: Roderigo Michael Cassio
Answer: Michael Cassio