Sea lettuce alga is
The sea lettuces comprise the genus Ulva, a group of edible green algae, that is widely distributed along the coasts of many oceans of the world. The lettuce type species within the genus Ulva is Ulva lactuca, lactuca is the Latin name for "lettuce". Few members of this genus are known under the common name, green nori. Individual blades of Ulva can grow more than 400m but this only occurs when the plants are growing in sheltered areas. Thus, the correct answer is option A.