* If your teacher is asking about the subject of information technology: You would spell it "IT".
* If your teacher is asking about the pronoun used to refer to something already mentioned: You would spell it "it".
For example:
* Teacher: "What are you planning to study in college?"
* You: "I'm interested in IT." (Information Technology)
* Teacher: "Did you finish your homework?"
* You: "Yes, I finished it." (The homework)
Make sure you understand the context of the question before answering! 😊