Can someone please explain why (E) is incorrect?

I understand that the passage is primarily about Pocock, as Ravi pointed out in his explanation, but my biggest takeaway was that it was his illumination of the idea that the literary tradition in which historical texts are written in which was his biggest contribution -- essentially, he was the first to thoroughly investigate this idea. My impression of (C) is that the main point is to advocate for the use of Pocock's approach, not to highlight his contribution to his field. My impression of (E) is that Pocock made a significant contribution to his field through his innovative approach, extending and adding to linguistic historians' understanding of historical texts. In short, why should we be choosing C over E?