The correct option is A Porphyra
Asexual reproduction by non-motile spores is seen in red algae. In the given options, Porphyra is a red alga.
Brown algae reproduce asexually by producing biflagellate zoospores that are pear-shaped and have two unequal sized laterally attached flagella. Ectocarpus and kelps are brown algae.
Asexual reproduction is by flagellated zoospores in green algae.
Chlamydomonas is a green alga.