The answer is: B.
This photo is of a fish kill in a waterway in Louisiana. During summers along the Gulf, fish kills are common, but usually affect a single species. Here the surface is covered with dead fish, crabs, stingray, eel, and possibly a whale (one was found nearby). Residents suspect this might be more fallout from the BP oil spill. When oil-eating microbes were used in the Gulf, scientists worried they would suck up large amounts of oxygen in consuming the oil, leading to more dead zones on the coast. Currently, no tests are under way to see if the two events are connected.