Explanation:

The correct option is (C) Argemone mexicana. *Argemone mexicana*, commonly known as Mexican poppy, is a terrestrial weed typically found in dry, disturbed soils and agricultural fields, not in aquatic environments. Its seeds are known to be toxic. Option (A) Eichhornia crassipes (water hyacinth) is a highly invasive free-floating aquatic weed. Option (B) Nymphaea alba (white water lily) is an aquatic plant that can sometimes become a weed in certain water bodies. Option (D) Azolla pinnata is a small, free-floating aquatic fern that can also be considered an aquatic weed due to its rapid growth.