Read the excerpt from the poem "Barbara Frietchie.”

Up rose old Barbara Frietchie then,
Bowed with her fourscore years and ten
Bravest of all in Frederick town,
She took up the flag the men hauled down;
How do the rhyming couplets move the action forward?
A. by including descriptive details about setting
B. by connecting important plot points
C. by illustrating the author's purpose
D. by using the same number of syllables