Unicellular organism - Chlorella
Biflagellate zoospores - Brown algae
Gemma cups - Marchantia
Uniflagellate gametes - Polysiphonia
(a) Gemma cups are the green, multicellular, asexual bud present in the thallus helps in asexual reproduction in Marchantia (b) Polysiphonia is a red algae. They do not possess uniflagellate gametes and sexually reproduces by non-motile gametes (c) Chlorella is the unicellular algae and belongs to Chlorophyceae (d) Biflagellate zoospores are the pear-shaped structure with two unequal laterally attached flagella. It helps in asexual reproduction in brown algae. Thus, the correct answer is option B.