Answer: an
Step-by-step explanation:
"You are an intelligent student"
- Because the question is describing someone, we must use articles a and an. In this case it is an because there is a vowel starting the next word after the blank, which is "intelligent"
- Any word that starts with a vowel (a, e, i, o, u, and sometimes y) must use the article an because it is all about sound and sounding out.