The rust fungi completing their life cycle on one host are called

Answer: Option B

The rust fungi completing their life cycle on one host are called autoecious.
Autoecious rust is an obligate parasitic fungus that needs a single host species to complete its life cycle. So, the autoecious rust fungus spends all stages of the life cycle in one specific host organism. Fungi belonging to Urediniomycetes are autoecious rust fungi.