Concept:Autotrophs are organisms that can produce their own food using sunlight or inorganic sources.Explanation:Plants and algae are autotrophs because they perform photosynthesis.Photosynthesis uses sunlight, water, and carbon dioxide to make glucose and oxygen.Humans, animals, and fungi cannot make their own food. They are heterotrophs and depend on others for nutrition.Among the given options, only algae is an autotroph.Answer:B. Algae