Final answer:
The word that correctly completes the sentence is 'more intelligent'.
Step-by-step explanation:
The word that correctly completes the sentence is more intelligent. When comparing two people or things, we use the comparative form of the adjective, which is formed by adding -er to the end of the adjective. Therefore, in this sentence, we need to use the comparative form of the adjective 'intelligent' to show that the student is more intelligent than the teacher.
Learn more about Comparative adjectives