Hint: Gametangial copulation is the complete fusion of the contents of two compatible gametangia. The two gametangia come closer to each other and the fusion of the cellular wall takes place. It takes place in fungi.
To solve this question, we must know about the gametangial copulation in fungi.
The Gametangial copulation occurs by two ways-
The contents of the gametangium fuse with one another through a pore.
Direct fusion of the cell takes place to form a single cell which occurs due to the dissolution of the cell wall at the point of contact. It takes place in the fungal class zygomycetes.
Zygomycetes are also known as conjugation fungi. They lack a hyphal cell wall in the reproductive stages. Common example of zygomycetes is mold.
Ascomycetes- There fungal class produces microscopic spores inside special sacs known as ascii. They mostly reproduce asexually.
Deuteromycetes- This fungal class do not possess sexual structures. It is also known as imperfect fungi.
Phycomycetes-They are also called algal fungi. The sexual mode of reproduction is similar to that of algae.
Hence, the correct answer is option (B)
Note: The species belonging to zygomycetes are mostly terrestrial living on soil or on dead decaying matter of both plants and animals. Unlike other fungi, their cell wall is composed of chitosan instead of chitin. A pheromone called trisporic acid is present in zygomycetes which is responsible for cellular differentiation.