Assertion: Achlorophyllous, multicellular and eukaryotic decomposers are fungi
Reason: Fungi have cell wall rich in cellulose and specialized chitin
A. Both assertion and reason are correct and the reason is the correct explanation for assertion
B. Both assertion and reason are correct but the reason is not the correct explanation for assertion
C. Assertion is correct but the reason is incorrect
D. Both assertion and reason are incorrect

Hint: Fungi are a kingdom of heterotrophic, typically multicellular eukaryotic species that do not make their own food and have important roles in an environment for nutrient cycling.

Complete answer: Fungi are eukaryotic organisms that include yeasts, moulds and mushrooms. The species found in the kingdom Fungi contain a cell wall and are widespread. Among living organisms, they are known as heterotrophs. There are some characteristics of fungi, which are as follows:
a) They may be single species or multicellular organisms.
b) Fungi have a cell wall composed of chitin and polysaccharides, as well as cellulose.
c) The protoplast includes the cell wall, which is divided into other parts of the cell, such as the cell membrane, cytoplasm, cell organelles and nuclei.
d) Fungi are cells that are eukaryotic, non-vascular, non-motile and heterotrophic.
e) They can be multicellular or unicellular.
f) Fungi lack chlorophyll and are thus unable to carry out photosynthesis.
g) Chitin biosynthesis occurs in fungi.
By releasing enzymes to break down the decaying material, fungi decompose organic matter, after which they absorb the nutrients into the decaying material. Thus, from the above discussion, we conclude that both assertion and reason are correct but the reason is not the correct explanation of assertion.
Hence, the correct answer is option B.

Note: Fungi are one of the most significant classes of species on the earth since they play a crucial role in the biosphere and they are of considerable economic value. Some of the major uses of fungi are;
i. Food: Cultivated species of fungi are edible and are used by humans as food.
ii. Medicines: There are many fungi that are used in humans and animals to manufacture antibiotics and control diseases. The antibiotic penicillin is extracted from a popular Penicillium fungus.