If Nusrat waters the plants, then the plants stay green. If the plants stay green, then the garden wins a prize. It is known that Nusrat waters the plants. Which of the following must be true?
Correct answer C. The garden wins a prize.
Explanation
Since Nusrat waters the plants, the first rule shows that the plants stay green. The second rule then shows that the garden wins a prize. This is modus ponens applied twice along the chain.
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