The correct option is C All fungi possess a purely cellulosic cell wall.
The cell wall in fungi is composed of chitin and polysaccharides. Only certain fungi, e.g., oomycetes have a purely cellulosic cell wall.
Therefore, all fungi do not have a purely cellulosic cell wall.
Hence, the statement in option c is incorrect.
Fungi are multicellular eukaryotes, however, certain fungi such as yeast are unicellular.
Hence, the statements in option a and b are correct.
Fungi exhibit heterotrophic modes of nutrition. Majority of fungi are saprophytic and absorb soluble organic matter from dead organisms. Some fungi show parasitic modes of nutrition and derive nourishment from the living host.
The statement in option d is correct.
Hence, the correct answer is option c.