Select the incorrect statement regarding reproduction in Rhodophyceae.
A. Asexual reproduction occurs by non-motile spores.
B. Sexual reproduction occurs by motile gametes.
C. Sexual reproduction is oogamous.
D. Complex post-fertilisation developmental events occur

Hint: Rhodophyceae is also known as red algae and belongs to eukaryotic algae which is one of the oldest groups. Rhodophyceae is one of the largest phyla of algae with over 7,000 recognized species.

Complete answer:
Majority of the Rhodophyceae algae are found in class Florideophyceae which are multicellular, marine algae with notable seaweeds. Red algae have eukaryotic cells without flagella and centrioles and contain chloroplasts which lack external endoplasmic reticulum and contain thylakoids. These algae contain phycobiliproteins pigment which provides them their red color. Most algae are multicellular, marine, and macroscopic and reproduce sexually.
Red algae can reproduce by sexual as well as asexual reproduction. Asexual reproduction can occur by vegetative means like fragmentation, cell division or propagules production as well as through production of spores. Sexual reproduction is oogamous and occurs through male and female gametes. Red algae do not have motile sperm and are dependent on water currents to transport their male gamete to female gamete. The Trichogyne continues to grow until it fertilizes with spermatium which results in thickening of the cell wall, separating it from the rest of the carpogonium at its base. After this separation the walls of the spermatium and carpogonium dissolve and male nucleus divide and move into carpogonium.

Hence, the correct option is B. Sexual reproduction occurs by motile gametes.

Note: Red algae display alternation of generations, along with gametophyte generation, many have two sporophyte generations. Carposporophyte produces carpospores which germinate into tetrasporophyte and produce spore tetrads which germinate into gametophytes.