What part of the essay do the following sentences most likely represent?

Another similarity between the spring and fall seasons is the rapid change that is visible from one day to the next. Just by looking out the window daily in the spring, you can observe the gradual process of the tree leaves opening. Each morning will bring new growth and noticeable transformation. In the same way, if you keep an eye on the trees out your window in the fall, you'll notice the colors of the leaves changing from orange to red, as well as the ever-mounting pile of leaves on the ground.

A. Support
B. Introduction
C. Thesis
D. Conclusion