Question

Around me stood the oaks and firs;

Answer 1

D. The speaker will only find perfection when he lets go of his preconceived notions of beauty.

Answer 2

The correct answer on the test was. . .

B) The speaker, by living in the moment of that scene, can understand how all the pieces work together in harmony.

because

This line ,the last in the poem (I yielded myself to the perfect whole.), is meant to emphasize the theme of the whole poem.  The theme of this poem is one that is very much in keeping with transcendentalism, the philosophy that Emerson was connected with.  Transcendentalism emphasizes (among other things) the idea that all of creation is in some way connected and that we as human beings are simply part of that creation.