Please choose the correct answer to the question: Students want to plant a lemon tree at their school, but the cold winter temperatures in Massachusetts would kill the tree. Which of the following is the best solution to this problem?

Answer1: planting several lemon trees together in a row Answer2: building a greenhouse to shelter the lemon tree Answer3: giving the lemon tree extra fertilizer in the winter Answer4: tying a stake to the lemon tree for support during the winter

Answer format: answer1/answer2/answer3/answer4