Answer: The answer is B.
Explanation: You're means You are. The only sentence that it makes sense in is B. "You're going to be late for practice." In other words "You are going to be late for practice."
Brian save the pieces of aluminum from the <span>fuselage to be used by him in his stay in the forest. He could use it to signal airplanes hovering above the forest by finding sunlight. The light that would be reflected with the aluminum can catch the attention of possible airplane flying above him.</span>