Act iii of the tragedy of macbeth serves mainly to a. introduce the play’s climax. b. expose macbeth’s mounting troubles. c. introduce important new characters. d. resolve the play’s central conflicts.

Act III of The Tragedy of Macbeth serves mainly to  expose Macbeth’s mounting troubles. Option B is correct.

The Tragedy of Macbeth dramatises the damaging physical and psychological impacts of political ambition on those who seek power for its own sake.

Macbeths illustrates the playwright's relationship with his sovereign.

Shakespeare's source for the story is the account of Macbeth, King of Scotland; Macduff; and Duncan.