I will go with E
because its said "there is no essential difference between human and animal intelligence." it not said "There's no difference between human and animal intelligence"
If there was disagreement about whether the difference was the ability to construct sentences, think symbolically, or create tools, at least there was broad agreement that there were intrinsic differences between human and animal intelligence. Debate centered on the question of what it was that made the human mind qualitatively different, and not whether it was qualitatively different at all. Language-using apes have eroded that earlier notion and also exposed uncertainty over the proper definition of human intellectual abilities. The animal/human dichotomy that has guided our thinking about language has given the investigation of language a curious circularity. Starting with the assumption that there were no continuities between animal and human language, we have looked for evidence to support this assumption, and then used this evidence to justify the assumption.