Step 1: Understanding the truth table method.
To test the validity of an argument using a truth table, we follow these steps: - B. Assigning consistent truth values to all variables: Set up truth values for all variables. - D. Reducing the argument into a conditional statement form: Express the argument as a conditional statement (if-then). - C. Assuming the statement to be false: Assume the conclusion is false to check for contradiction from premises. - A. Assuming the antecedent of the statement to be true and consequent to be false: Critically check the argument's logical flow.
Step 2: Conclusion. The correct order is B, D, C, A.
Final Answer: \[ \boxed{\text{The correct answer is 1. B, D, C, A.}} \]