Final answer:
Using the principles of logical form and deductive reasoning, the correct conclusion that follows in a single step from the given premises is option b: \( (P \cdot M) \supset \sim R \), which uses tautology to reduce the premise to a simpler form.
Step-by-step explanation:
The question involves using logical form and deductive reasoning to select a conclusion that follows in a single step from the given premises. Here are the premises:
- \( \sim P \)
- \( L \supset (P \lor M) \)
- \( (P \cdot M) \supset (\sim R \lor \sim R) \)
We are asked to select from the options a conclusion that follows in a single step. When we apply valid deductive inferences such as disjunctive syllogism, modus ponens, and modus tollens, it becomes clear that the correct answer is:
\( (P \cdot M) \supset \sim R \) (3, Taut)
This uses tautology, where \( \sim R \lor \sim R \) simplifies to \( \sim R \), as the presence of the same term in a disjunction is redundant. Thus, the conclusion is that if both P and M are true, then R must not be true, following directly from premise 3.