Answer:
<h2>Order.</h2>
Step-by-step explanation:
When we are proving a proposition, it's important to have order in our 2-column proof.
<em>So, we must have a left colum for Statements and a right colum for Reasons, that's the order we need to have.</em>
In the statements colum we write our deductions. In the reasons column, we write the justification or reason about our deduction.
Therefore, the right answer is the third choice: Order.