Design a concise dietary rule for pregnant people that integrates biomagnification principles to minimize mercury exposure from seafood, and choose the option that best synthesizes the scientific concept into actionable guidance.

Eat only farmed fish because farming eliminates biomagnification entirely in all cases and guarantees zero mercury accumulation regardless of species, origin, or feeding practices.

Avoid all fish entirely during pregnancy because the possibility of any mercury exposure outweighs the nutritional benefits of omega-3s, making seafood universally unsafe for this group.

Select fish solely based on price and availability because economical choices will naturally include species with low mercury, removing the need to consider trophic level or biomagnification when planning diet.

Prefer low-trophic-level fish (small, shorter-lived species like sardines, anchovies, and salmon) and avoid high-trophic-level predatory fish (e.g., tuna, swordfish, shark) that biomagnify mercury through the food chain; limit overall seafood portions to recommended weekly servings.