Answer:
B is the complete sentence.
Explanation:
This is because the transition word "when" is used to link two complete sentences.
When links the two sentences "everyone left the party" and "the room was full of tables, and the floor was covered with confetti.
The sentence everyone left the party is a complete sentence because it has a subject (everyone) followed by a verb (left).
The sentence the room was full of tables and the floor was covered with confetti is a complete sentence because it has two subjects (the room, the floor) followed by two verbs ( was full of, covered).
A is not a complete sentence because After links a sentence with a fragment. "Complete with fireworks" does not have a subject, nor a verb, so it cannot be a complete sentence.
B is not a complete sentence because it has a linkage, "Now that", with no second sentence. It only has the one sentence of "captain is the head of our school football team.
Hope this helps!
