The correct option is D Ulva
Sea lettuce or Ulva lactuca is a species of bright green algae of the division Chlorophyta. With its lobed and ruffle-edged leaves, this flat green sea weed resembles a garden lettuce and is found in marine waters growing from a discoid holdfast. Commonly found on rocks and other algae the sea lettuce is prolific, where the nutrients are in abundance. The life cycle of Ulva shows the sporangial and gametangial thalli as morphologically alike and follows a pattern of alternation of generations and the multi-cellular diploid form alternates with multi-cellular haploid form. Thus, the correct answer is option D.