The correct option is A Large, coloured and scented
Insects such as butterflies, moths and bees visit flowers for nectar. These flowers have to be large, colored, showy and scented so that they can be easily spotted by insects. While feeding on nectar the pollens attach onto their body. When the same insect visits another flower it transfers the pollen to the stigma of that flower leading to pollination. Thus the correct answer is option C.