Which group of words is a complete sentence?

a.
the ball started to roll down the street.

b.
a group of graceful dancers.

c.
the squealing pigs in the old red barn.

d.
walked on the path together.

Alittle later than his thisbe had, and he could see what surely were the tracks of a wild beast left clearly on deep dust. his face grew ashen. and when he had found the bloodstained shawl, he cried: "now this same night will see two lovers lose their lives: she was the one more worthy of long life: it's i who bear the guilt for this. which statement best describes how the order of events creates tension?