Answer:
The evidence which suggests that the dagger Macbeth sees is an illusion is:
"a false creation, proceeding from the heat-oppressed brain?"
Step-by-step explanation:
In Act II Scene 1, the appearance of the dagger symbolizes the thoughts prevailing in the mind of Macbeth. He is struck between the feeling of guilt of killing the King and the temptation of becoming a King himself. He sees the image of the dagger hanging just next to him but he was unable to catch it by any trial.