Step 1: Assertion (A) is correct as it reflects the widely recognized view that consuming a diet rich in diverse vegetables, fruits, and plant-based foods can lower cancer risk due to beneficial phytochemicals.
Step 2: Reason (R) is also accurate, acknowledging that non-nutritive components like fiber and phytochemicals are part of a healthy diet. However, Reason (R) does not directly explain how these components reduce cancer risk, thus it does not provide a sufficient explanation for Assertion (A).