Solution

Mucor is a microbial genus of approximately 6 species of moulds commonly found in soil, digestive systems, plant surfaces and rotten vegetable matter. Mucor mucedo uses asexual reproduction. During sexual reproduction, compatible strains form short, specialized hyphae called as gametangia.
Agaricus is a genus of mushrooms containing both edible and poisonous species, with possibly over 300 members worldwide. The genus includes the common button mushroom (Agaricus bisporus) and the field mushroom (Agaricus campestris), the dominant cultivated mushrooms of the West.
Phytophthora is a genus of plant-damaging Oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as well as environmental damage in natural ecosystems. Phytophthora spp. are mostly pathogens of dicotyledons, and are relatively host-specific parasites.
Alternaria is a genus of ascomycete fungi. Alternaria species are known as major plant pathogens. They are also common allergens in humans, growing indoors and causing hay fever or hypersensitivity reactions that sometimes lead to asthma.
Thus, the correct answer is option D.