What does emerson most likely mean here when he refers to the "reduction ad absurdum of slavery"?

After doing some research, I believe you are referring to this text with the following choices for the question. 

"Indeed, it is the reduction ad absurdum of Slavery, when the governor of Virginia is forced to hang a man whom he declares to be a man of the most integrity, truthfulness and courage he has ever met."

A. It is absurd to declare someone is a man of integrity while sending him to the gallows.
B. For a man of integrity to be executed while slave owners run free is an absurd notion.
C.Slavery can only lead to absurd conclusions because the premises are flawed to begin with.
D.These are absurd times if men of integrity are being sentenced to hang for what they believe in.

When Emerson referred to "reduction ad absurdum of slavery", he most likely means that: "Slavery can only lead to absurd conclusions because the premises are flawed to begin with."

It's considered to be association or connection