Read this excerpt from Phillis Wheatley's poem "To His Excellency General Washington," and complete the sentence that follows. Celestial choir! enthron'd in realms of light,
Columbla's scenes of glorious toils I write.
While freedom's cause her anxious breast alarms,
She flashes dreadful in refulgent arms.
See mother earth her offspring's fate bemoan,
And nations gaze at scenes before unknown!
See the bright beams of heaven's revolving light
Involved in sorrows and the veil of night!

The lambic pentameter in the poem creates an even (tone, rhythm, verse, music)
and complements the poem as a (couplet, metaphor, Meter)

Please help out and pick which one for the lines.