What literary device is shakespear using in the passage?

Macbeth Act IV, Scene ii

HECATE: O well done! I commend your pains;
And every one shall share i' the gains;
And now about the cauldron sing,
Live elves and fairies in a ring,
Enchanting all that you put in.


A. Sarcasm
B.Tone
C.Understandment
D. Irony