Answer:
An Echo.
Explanation:
An echo can be defined as a reflection of sound. But in the literary context, an echo is a reflection of something.
In Scene 5, of the play, Faustus bargains his soul with Lucifer. He signs the contract, according to which, Faustus will be provided pleasures of the world and assistance of Lucifer's powerful assistant, i.e., Mephistopheles, for twenty-four years. And after the completion of twenty-four years, the soul of Faustus will be taken into hell for eternity, depriving him of eternal bliss of heaven. Though good angel warns him, even his blood tries to stop him from selling his soul, but he sells his soul.
In Scene 13, twenty-four years of Faustus's pleasurable life is over and now his time of eternal death is near. This scene is echoing the incident of Scene 5 in which he signed a deal with Lucifer, and now in Scene 13, it has come to its maturity.
So, the correct answer is an echo.