Grass Flowers Lack Petals and Sepals

Grass flowers lack petals and sepals. Which of the following statements is TRUE?

A) They are imperfect flowers lacking stamen or carpals.
B) They are incomplete flowers lacking one or more floral parts.
C) These flowers are pollinated at night, so they donʹt benefit from showy petals or sepals.
D) They are pollinated by flies, which donʹt require showy, scented petals.