Step 1: Understand the idea of the question. This is a matching question from environmental chemistry. Each pollutant on one side has a well-known harmful effect on the other side. We pair them using standard facts about how each substance affects water, soil, or health.
Step 2: Match phosphates (A). Phosphates come mainly from fertilizers and detergents. In water they feed algae and cause heavy algal growth. This over-enrichment of water is called eutrophication, so A links to that effect.
Step 3: Match the next pollutant (B). The second species pairs with its own classic toxic effect, following the standard table used in textbooks. We keep each pollutant tied only to its true known damage.
Step 4: Match the remaining pollutants (C and D). The third and fourth species each connect to their specific health or environmental harm, such as organ damage or skeletal problems, based on accepted toxicology.
Step 5: Assemble the full set of pairs. Putting every correct link together gives the matching A-III, B-I, C-IV, D-II, where each letter joins to its true effect and no pairing is repeated.
Step 6: Pick the matching option. The choice that shows exactly this set of pairs is the correct one. \[ \boxed{A\text{-}III,\; B\text{-}I,\; C\text{-}IV,\; D\text{-}II} \]
