The correct answers are to study medicine; adverb.
Infinitive phrases are relatively easy to spot - they begin with the word to, are followed by the main verb, and the rest of the words closely connected in meaning. In the example above, the infinitive phrase is <em>to study medicine - </em>we have the word <em>to, </em>the verb <em>study, </em>and the object <em>medicine. </em>(Even though the phrase <em>to college </em>also begins with <em>to, college </em>is not a verb but rather a noun - this is a prepositional phrase).
The use of the infinitive phrase is adverbial - it means that it can tell us the time, place, manner, etc. of the verb, of the action being performed. In the example above, we see the reason why <em>Candice went to college. </em>
