Which of the Following Observations Led to the Conclusion That

Which of the following observations led to the conclusion that the food competition hypothesis for giraffe neck length might not be correct?

A) In the populations studied to date,giraffes never feed high in trees.
B) In certain populations at certain times of year,only male giraffes feed high in trees.
C) Male and female giraffes spend most of their time feeding low in trees.
D) Giraffes rarely die of starvation,so food availability is unimportant.