The correct answer is C-zooplankton.
DDT passes up the food chain and its concentration increases (biomagnifies) higher up the food chain.
DDT is dangerous because it is water insoluble and hardly breakable. Since, DDT is fat-soluble, animals store it in fatty tissues.
If a predator, in this case largemouth bass, consumes multiple leopard frogs and each of them has a small amount of DDT, the amount of DDT in the bass will be the result of all of those small amounts combined.
