The passage tells us that Haraway is innovative in a way she incorporates broad cultural issues into her analysis (lines 43-44), suggesting that this approach is uncommon, hence the "innovative" part. It further tells us that despite decades of rhetoric from historians about the need to unite the issues external and internal to science, that dichotomy has proved difficult to set aside. Generally one of the definitions of rhetoric is "insincere or grandiloquent language" . With this in mind, we can understand this statement as saying that historians have been taking about the need to incorporate the external, including social, cultural etc., issues, but never had any intent to actually implement this innovative idea in practice. (C) accurately states that the author uses the term "rhetoric" to point out that all the conversation about the need to unite external/ internal issues has simply been an empty talk that never materialized.
