Which play is an example of a play within a play?

The correct choice is a play that incorporates a play within its narrative structure, allowing the characters to engage with a performance that influences the main plot. In "Hamlet," there is a famous scene called "The play within the play," which is represented by the performance of "The Murder of Gonzago." This play is staged by Hamlet to gauge King Claudius's guilt concerning the murder of Hamlet's father. Through the characters watching the performance, vital themes are explored, and key developments in the plot occur, illustrating the impact of theater and performance on reality.

In contrast, the other works listed do not feature a play within the play in the same manner. "Macbeth" focuses on ambition and guilt without incorporating such a dramatic device. "A Midsummer Night’s Dream" includes performances but is framed differently and does not have the same level of direct interaction with the main plot. "Othello" primarily deals with themes of jealousy and betrayal without utilizing a play in this way. Therefore, "Hamlet" serves as the quintessential example of a play within a play, making it the right answer.