D. Macduff does indeed kill Macbeth in act 5, scene 8.

What happened in Act 5 Scene 7 of Macbeth?

Macbeth kills Young Siward, the son of one of the English commanders. Macduff searches frantically for Macbeth, vowing that he and he alone should kill the king. Finally, Siward tells Malcolm that they've overtaken Dunsinane castle, and victory is near. ... But Macduff won't let him get off that easily.

Who dies in Act 4 Scene 2 Macbeth?

The murder of Lady Macduff and her young son in Act 4, scene 2, marks the moment in which Macbeth descends into utter madness, killing neither for political gain nor to silence an enemy, but simply out of a furious desire to do harm.