BOTANY

Detailed explanation-1: -A. Lotus: Lotus is also known as Nelumbo Nucifera which is an aquatic plant and informally called as a water lily.

Detailed explanation-2: -Nelumbo nucifera, also known as sacred lotus, Laxmi lotus, Indian lotus, or simply lotus, is one of two extant species of aquatic plant in the family Nelumbonaceae. It is sometimes colloquially called a water lily, though this more often refers to members of the family Nymphaeaceae.

Detailed explanation-3: -Plants that grow in water are aquatic plants. From the given options lotus, duckweed and water lily are aquatic plants.

Detailed explanation-4: -Lotus has developed the following adaptations to live in water: The roots specialized to take in oxygen from water. The leaves are flat hence they help in floating. Air sacs present also help in floating.