The answer is letter A. A business letter is a letter written in formal dialect, typically utilized when composing starting with one business association then onto the next, or for correspondence between such associations and their clients, customers and other outside gatherings.
The answer is:
It represents his depart from China to begin a new life in the United States.
In the poem "Garden of My Childhood," the author Kuangchi Chang compares his native country China to a childhood garden and mentions his decision to leave it for a new garden, meaning America. Moreover, he wonders what the future will bring there.