Smut fungi in millets are
I. Autoecious in nature II. Heteroecious in nature III. Cause systemic infection IV. Infect inflorescence

Correct option is A

Smut fungi complete life cycle on a single host.
Hence, they are autoecious. They cause systemic infection in host plants.
The infection mainly appears on inflorescence. They are not heteroecious.
Thus, statements I, III and IV are correct. Therefore, option (A) is correct.