Help!!! Arthur is studying plants, and he wants to learn more about why tree leaves change colors in the fall. His teacher suggested that he do a scientific experiment, starting with making a testable hypothesis. Which of the choices below is a possible hypothesis for Arthur to investigate?

A.
If I water the trees in my yard all winter, will they stay green until spring?
B.
If I stop watering the trees in my yard early in the summertime, their leaves will change color before the neighbors' trees change.
C.
My house has more trees around it than any other house on our street.
D.
Why do some leaves change colors, and others don't?