Answer:
The correct answer option 2. Ulva.
Explanation:
Ulva is a flat green multicellular alga growing from a discoid holdfast. The membrane of the Ulva is 2 cells thin, translucent, and soft and grows attached with or without small disc-shaped holdfast.
The chloroplast is cup-shaped in some cases but a parietal plate in others with 1 to 3 pyrenoids in number. There are some Ulva species that are similar and difficult to differentiate.
Thus, the correct answer is option 2. Ulva.