The tone of the author of the passage in describing theories of co-evolution can best be described as one of
(A) appreciation of the theory’s ability to explain the disappearance of certain carbohydrate-rich plant species (B) admiration for the theory’s refutation of the seed-disbursal theory of the disappearance of the carbohydrate-rich plant species (C) skepticism toward the theory’s ability to account for the evolution of trade relations between agriculturalists and foragers (D) annoyance at the theory’s failure to account for such phenomenon as the success of the sago palm (E) concern that the theory may be insufficient to discredit the Headland Hypothesis