You discover a new species of plant with flowers that varies in color from yellow to green to blue. After careful observations you conclude that a local species of hummingbird tends to visit flowers with more yellow in them, and the offspring plants have similar flower coloration as the parents

What final experiment would you have to do to test if there is natural selection in these plants on the trait of flower color ?
A). A cross breeding experiment to determine if the flower color is following Mendelian inheritance
B) Artificially manipulate the color of nonyellow flowers to be yellow to test whether the yellow color leads to more seed
C) Introduce a new species of pollinator and observe whether the frequency of yellow/ green/blue flowers changes over time
D) Count the number of offspring hummingbirds have to determine if there is a reproductive advantage for visiting yellow flowers compared to other