For each of the following arguments, use the STTT to determine whether the argument is valid or invalid. For some of these arguments, Steps 2 C , 3 C , and 4 (i.e., the C-Sequence) will be most efficient; for some of these arguments Steps 2 P , 3 P , and 4 (i.e., the P-Sequence) will be most efficient.

(P₁): (~ M ⋅ ~ N) ⊃ (O ⊃ N)
(P₂): N ⊃ M
(P₃): ~ M
∴ ~ O