The question asks for something that can be "correctly inferred," making this an Inference question. Look for ways to combine statements to make logical deductions.
According to the stimulus, some people eat foods that contain significant amounts of omega-3 fatty acids, which are known to help prevent blood clots.
Combining these two statements, it can be deduced that some people are lowering their chances of developing blood clots.
(D) combines the given statements and is correct. Since these foods are known to help prevent blood clots, it can be inferred that some people will lower their risk of blood clots by eating these foods.
(A) is extreme because it claims complete prevention of blood clots. The stimulus says only that omega-3 fatty acids help prevent blood clots.
(B) is not a valid inference. Flax seeds are just one source of omega-3 fatty acids. Even without those seeds, there are plenty of other foods that can help prevent blood clots (e.g., salmon and sardines).
(C) is extreme. The foods listed are said to help, but the author never says they are the most effective. There is no information about other foods, any of which could be more effective.
(E) is extreme. The argument only addresses preventing blood clots, not leading an overall healthy lifestyle. Furthermore, even with regard to preventing blood clots, the stimulus just says foods with omega-3 fatty acids help, not that they are the only thing necessary.