The correct option is C wetlands
Wetland is believed to be the cradle of abundant animals and plants. It is considered the most biologically diverse ecosystem on the planet. Natural wetlands have been called the 'kidneys of the landscape' because of their ability to store, assimilate and transform contaminants lost from the land before they reach waterways.
Like a giant kidney, wetlands help to dilute and filter material that could otherwise harm our lakes, rivers and other waterways.
Too much of these substances flowing through waterways can cause harmful algae to bloom, raise water temperatures and even kill fish and other animals.