Final answer:
The characteristic of American Romanticism evident in the lines from Longfellow's "A Psalm of Life" is self-reliance.
Step-by-step explanation:
The characteristic of American Romanticism that is evident in the lines from Longfellow's "A Psalm of Life" is B. Self-reliance. In these lines, the speaker advises to "Trust no Future, howe'er pleasant! / Let the dead Past bury its dead!" This reflects the Romantic ideal of self-reliance, where the individual is urged to trust their own instincts and not be bound by societal conventions or the influence of the past.