The correct option is
A Plumose
The stigma can be modified to attain different texture and shape. In grasses, wind pollination is common and so the stigma is modified to capture the wind-borne pollen grains. This modification makes the stigma feathery, which is also called the plumose stigma.
A. Plumose is a feathery stigma.
B. Spur is the beak-like outgrowth of the sepals, example, Delphinium
C. Stylopodium is the conical expansion at the base of the style, example, Fennel
D. Calyculus is the modified leaf-like structure present at the base of the inflorescence.
Hence, the correct answer is 'Plumose'