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

question 295

Multiple Choice

determine whether the argument is valid or invalid. If it is invalid, select a counterexample.
-1. D ⊃ (E • F)
2) D ≡ (E $\lor$ ∼F) / ∼E ⊃ ∼D

• A) Valid
• B) Invalid. Counterexample when D, E, and F are false
• C) Invalid. Counterexample when F is true and D and E are false
• D) Invalid. Counterexample when D, E, and F are true
• E) Invalid. Counterexample when D and F are true and E is false