The correct option is B Biomagnification
Pesticides like DDT and elements like cadmium, arsenic, zinc and lead, when released into the soil from fertilisers are toxic to the environment. When these elements enter the food chain in aquatic or terrestrial ecosystem, there would be an increase in their concentration at each successive level. This happens because when a toxic substance gets accumulated in an organism along with food or water, itcannot be metabolised or excreted, and is thus passed on to the next higher trophic level and this phenomenon is called biomagnification. Eutrophication is the biological enrichment of an aquatic system by nutrients like nitrogen, phosphorus, etc. which can support the growth of aquatic producers.