Here are the correct answers for each question based on the context provided:

**Question 13:**
The correct answer is **C. have celebrated**.
The sentence would read: "We are excited to announce that our annual school fair will have celebrated on Friday..."

**Question 14:**
The correct answer is **B. supplies**.
The sentence would read: "There will be a variety of games, food supplies, and performances for everyone to enjoy."

**Question 15:**
The correct answer is **D. If**.
The sentence would read: "Please note, if it rains on February 2nd, the fair will be postponed to the following Friday, February 9th, 2024."

So the full answers are:
13: C
14: B
15: D