The Tragical History of Doctor Faustus
by Christopher Marlowe (excerpt)

FAUSTUS: One thing, good servant, let me crave of thee,
To glut the longing of my heart's desire,„
That I might have unto my paramour
That heavenly Helen which I saw of late,
Whose sweet embracings may extinguish clean
Those thoughts that do dissuade me from my vow,
And keep mine oath I made to Lucifer.

MEPHISTOPHELES: Faustus, this, or what else thou shalt desire,
Shall be perform'd in twinkling of an eye.

Which underlying theme is evident in this passage from a play?
exploitation of nature
the satisfaction of desire
personal sacrifice
conflict between duty and desire