The sentence that contains a participle functioning as a verb is: "Mateo will only eat cooked carrots."
In this case, "cooked" is the participle that describes the carrots and functions adjectivally; however, if you are looking for a participle functioning specifically as part of a verb phrase, "waiting" in "The students are waiting for the bus" serves as a present participle in the verb phrase "are waiting".
Thus, the best answer could be "The students are waiting for the bus."