The answer is D. Smut.
Mushrooms, yeast, and mold are all fungi, while smut is a type of plant disease caused by fungi.
Mushrooms are the fruiting bodies of fungi that grow above ground. They are typically fleshy and have a cap and stem. Mushrooms are used for food, medicine, and religious ceremonies.
Yeast is a type of fungus that is single-celled. It is used in baking and brewing to make bread, beer, and wine. Yeast is also used to make biofuels and to produce enzymes.
Mold is a type of fungus that grows on dead or decaying organic matter. It can be found on food, wood, and other surfaces. Mold can cause allergic reactions and respiratory problems.
Smut is a type of plant disease caused by fungi. It can affect a variety of plants, including corn, wheat, and barley. Smut causes the plant to produce black spores, which can spread to other plants.