【单选题】A study is under way in Yosemite National Forest to determine the height of adult American pine trees. Specifically, the study is attempting to determine what factors aid a tree in reaching heights gr...
A.
the 250 randomly selected adult American pine trees
B.
the 25,000 adult American pine trees in the forest
C.
all the adult American pine trees taller than 60 feet
D.
all American pine trees, of any age, in the forest