With reference to the formal proof of validity of the following argument, state the correct order of rules employed.
1. \( P \cdot Q \)
2. \( ( P \vee R ) \supset S / \therefore P \cdot S \)
3. P
4. \( P \vee R \)
5. S
6. \( P \cdot S \)
A. Conjunction
B. Modus Ponens
C. Addition
D. Simplification
Choose the correct answer from the options given below: