The correct option is D Uniflagellate gametes - Polysiphonia
Polysiphonia , which belongs to the red algae, produce non-motile gametes.
The zoospores of brown algae are biflagellate and help in asexual reproduction.
Asexual reproduction in liverworts like Marchantia takes place by the formation of specialised structures called gemmae which are green, multicellular, asexual buds, which develop in small receptacles called gemma cups located on the thalli.
Chlorella is a genus of single-celled green algae.