Read the sentence.

In ancient times, athletes, chosen by their city states, came to Olympia from every part of the Greek world.

Identify the phrase in bold.

Agerund phrase
Bparticipial phrase
Cinfinitive phrase
Dverb phrase

Verified Answer :

i have this phrase in bold  CHOSEN BY THEIR CITY STATES, according to this the answer is B. participial phrase.

Depending on which phrase is in bold, there can be many answers.
If the phrase that is bolded is chosen by their city states, then the correct answer is B) participial phrase, because it begins with a participle chosen.