Answer:
d. Petals
Step-by-step explanation:
Petals are the non-reproductive or accessory structures of flowers of flowering plants. Petals in most of the flowers are colored and beautiful. The function of petals is to attract the pollinators such as insects towards the flower to facilitate pollination. Grasses are the flowering plants that are mostly wind-pollinated. Therefore, the flowers of grasses do not require to have rewards such as nectar and the attraction sources such as petals for the pollinators. So, flowers of grasses have reduced petals.