A Before the buzzer, the runner tripped on a shoelace dangling from her shoe.
A participial phrase is a verb phrase that functions as an adjective and modifies a noun or a pronoun. The participial phrase is "dangling from her shoe". It uses the verb "dangling" and describes the shoelace which is a noun. Option B adds a prepositional phrase. Option C adds another main action verb. Option D adds a prepositional phrase.