B) Phil wanted to play video games, but he finished his homework first.
The infinitive phrase in this sentence is "to play video games". It answers the question - What did Phil want?. Since it's the direct object of the verb, it is a noun. Direct objects are always nouns. The infinitive phrase in option A is "to watch". The infinitive phrase in option C is "to cheer". Even though "to the away games" starts with to, it is a prepositional phrase because there is not a verb in the phrase. The infinitive phrase in option D is "to help anyone".
