The causal organism Neovossia indica produces

Answer: Option D

The causal organism Neovossia indica produces Teliospores.
Karnal bunt also known as partial bunt is a fungal disease of wheat, durum wheat, and triticale. The smut fungus Neovossia indica, a basidiomycete, invades the kernels and obtains nutrients from the endosperm.
The darkening of the kernel is a result of the kernel tissue being converted into a teliospore mass by the fungus. A teliospore that has successfully attached to a susceptible host will germinate to produce what is known as a promycelium.