Question

hamlet, part 6: applying literary criticism
gertrude: have you forgot me?
hamlet: no, by the rood, not so: (20)
you are the queen, your husband’s brother’s wife,
and,—would it were not so!—you are my mother.
gertrude: nay then, i’ll set those to you that can speak.
hamlet: come, come, and sit you down; you shall not budge;
you go not, till i set you up a glass (25)
where you may see the inmost part of you.
gertrude: what wilt thou do? thou wilt not murder me?
help, help, ho!
polonius: behind. what, ho! help! help! help!
hamlet: draws. how now! a rat? dead, for a ducat, dead! makes a pass through the arras. (30)
polonius: behind. o! i am slain.
gertrude: o me! what hast thou done?
hamlet: nay, i know not: is it the king?
gertrude: o! what a rash and bloody deed is this!
hamlet: a bloody deed! almost as bad, good mother, (35)
as kill a king, and marry with his brother.
gertrude: as kill a king!
hamlet: ay, lady, ’twas my word. lifts up the arras and discovers polonius.
what does hamlet do when he hears polonius behind the curtain?
he calls for help. he gets a mirror for his mother to look into. he kills polonius. he accuses polonius of killing king hamlet.

Explanation:

From the text, when Hamlet hears Polonius behind the curtain, the stage direction says "Hamlet: [Draws.] How now! a rat? Dead, for a ducat, dead! [Makes a pass through the arras.]" and then Polonius says "O! I am slain." This shows Hamlet kills Polonius. The other options are incorrect: he doesn't call for help (Polonius does), he was going to get a glass (mirror - like) for his mother earlier not when he hears Polonius, and he doesn't accuse Polonius of killing King Hamlet here.

Answer:

He kills Polonius.