Determine Whether the Argument Is Valid or Invalid $\lor$

Multiple Choice

determine whether the argument is valid or invalid. If it is invalid, select a counterexample.
-1. ∼(R $\lor$ S)
2) ∼R ⊃ (∼T ⊃ X)
3) T ≡ X / T

A) Valid
B) Invalid. Counterexample when R and S are true and T and X are false
C) Invalid. Counterexample when R is true and S, T, and X are false
D) Invalid. Counterexample when S is true and R, T, and X are false
E) Invalid. Counterexample when R, S, T, and X are false