In this excerpt from James Henry Hammond's speech "Cotton Is King," which piece of text uses an analogy to justify the existence of the institution of slavery?

Its the first sentence choice:

1. Such a class you must have, or you would not have that other class which leads progress, civilization, and refinement.

2. We use them for our purpose, and call them slaves.

3. The highest proof of what is Nature's law.

4. I will not characterize that class at the North by that term; but you have it; it is there; it is everywhere; it is eternal.