Read the second stanza from "Mutability.”We rest.—A dream has power to poison sleep; We rise.—One wandering thought pollutes the day; We feel, conceive or reason, laugh or weep; Embrace fond woe, or cast our cares away

The stanza says a dream can “poison sleep” and a wandering thought can “pollute the day,” showing that thoughts can spoil otherwise ordinary experiences. The final lines add that people may embrace sorrow or cast their cares away, so the stanza does not claim that only negative thoughts shape a life or that people are inherently negative. The best choice is A, thoughts can have negative effects.

AI-written and checked against the verified answer.