C). The adverb phrase 'in road races' modifies the word competes.
Explanation:
An adverb phrase exemplifies a group of words that is employed to modify the expressions like a verb, adjective or another adverb. It usually describes when, how, and where something occurs. In the given sentence, <em>the adverb phrase 'road races' that is modifying the verb 'competes' and answers the question, "where does Simon compete?". The answer is the adverbial phrase, 'Simon competes in road races".</em> Thus, <em>option C</em> is the correct answer.
