The correct answer is: C."Or art thou but / A dagger of the mind".
This option best demonstrates that the dagger Macbeth sees is an illusion, because Macbeth states that dagger he sees is possibly "a dagger of the mind". Macbeth is a famous play written by William Shakespeare. The plot of the play involves a Scottish general, called Macbeth, who believes a prophecy, and kills King Duncan, in order to replace King Duncan as the King of Scotland. After Macbeth kills the King, he experiences guilt and unrest, which in turn leads to him experiencing hallucinations. Thus, Macbeth sees daggers that are imaginary, as he experiences hallucinations.
The definition of a convention is a meeting or assembly of people who share a common interest or a convention is a method, practice, rule or custom. An example of convention is a national meeting of English teachers
A convention, in the sense of a meeting, is a gathering of individuals who meet at an arranged place and time in order to discuss or engage in some common interest. The most common conventions are based upon industry, profession, and fandom
a way in which something is usually done. "to attract the best patrons the movie houses had to ape the conventions and the standards of theatres"
an agreement between states covering particular matters, especially one less formal than a treaty. "the convention, signed by the six states bordering on the Black Sea, aims to prevent further pollution"
