The correct option is: (a) are pathogens
Explanation:
The rusts, smuts and mushrooms belong to the Class Basidiomycetes and produce basidiospores. They belong to the group of pathogenic fungi. Rusts come under order Uredinales, e.g., Puccinia graminis causes black rust of wheat. Smuts come under Order Ustilaginales which produce teliotospores. Mushrooms are placed in the Order Agaricales. Amanita and Marasmius are pathogenic fungi. Marasmius ordeades causes fairy rings on turf grasses.
