Recently, animal right advocates have shown a willingness to allow

Recently, animal right advocates have shown a willingness to allow scientists to perform cruel experiments on snakes and rats. This willingness betrays the very principles on which our movement depends. Protesting only the misuses of dogs, cats and chimpanzees is not enough. The same rights must be granted to all animals, regardless of how they strike our aesthetic sense. The line drawn between dogs and snakes is every bit as intolerable as that drawn between humans and dogs.

Which of the following best describes the purpose of the sentence highlighted in bold?

(A) It is the author's primary conclusion.

(B) It uses an example and analogy to add emphasis.

(C) It is the primary support of the conclusion.

(D) It implicitly rebuts criticism of the author's main point.

(E) It is irrelevant to the phenomenon described.