The sentence describes two mechanisms - careful selection of referees and concealment of authors' identities - that together serve "a single overriding purpose." The blank names that purpose. Both mechanisms are designed to prevent bias: editors select referees carefully to avoid incompetent or prejudiced reviewers, and author identities are concealed so that personal reputations do not influence judgment. The blank must therefore mean fairness, neutrality, or freedom from bias.

The correct pair must be tight synonyms that both mean objective, unbiased judgment.
- A. durability - The ability to last over time; enduring quality. While durability might be a desirable trait for academic work, neither referee selection nor author anonymity is primarily designed to ensure that scholarship endures. Incorrect.
- B. ingenuity - Cleverness, originality, inventive skill. Concealing authors' identities and carefully choosing referees are procedural safeguards, not methods for stimulating creativity. Incorrect.
- C. impartiality - Equal treatment of all parties; freedom from bias or prejudice. Both mechanisms - careful referee selection and author anonymity - are classic safeguards to ensure impartial evaluation. Correct.
- D. exhaustiveness - Completeness, thoroughness, comprehensiveness. While thorough review is desirable, the two mechanisms specifically target bias, not completeness. A review can be exhaustive yet biased; these mechanisms prevent the latter. Incorrect.
- E. disinterestedness - Freedom from personal interest or bias; objective neutrality.
"Preservation of disinterestedness" produces a sentence virtually identical in meaning to the one with "impartiality." Both name the quality of unbiased judgment that the two mechanisms are designed to protect. Correct.
- F. novelty - Newness, originality, the quality of being novel. Like "ingenuity," this describes intellectual content, not procedural fairness. Incorrect.