Truth of Assertion (A): The assertion about the correlation between high-fat diets, lack of exercise, stress, and heart problems is widely supported by medical research. So, A is true.
Truth of Reason (R): The reason explains how high-fat diets can lead to blood clotting and reduced blood flow to the heart. This is also supported by medical knowledge. So, R is true.
Relationship: The reason provides a direct explanation for the assertion. If fatty diets contribute to clots in the arteries, this indeed can lead to heart problems as stated in the assertion.The correct option is (A): if both 'A' and 'R' are true and 'R' is the correct explanation of 'A'.