Final answer:
The attribute unique to the audit work of CPAs, compared with work performed by attorneys or practitioners of other business professions, is independence.
Step-by-step explanation:
The attribute unique to the audit work of CPAs, compared with work performed by attorneys or practitioners of other business professions, is independence. CPAs are required to maintain independence in their audit work to ensure the integrity and objectivity of their opinions and conclusions. This means that they must be free from any conflicts of interest and have impartial judgment when assessing an organization's financial statements. Attorneys, on the other hand, may advocate for their clients and represent their interests. While due professional care (A), competence (B), and a complex underlying body of professional knowledge (D) are essential attributes for all professionals, independence (C) is distinctively critical for CPAs in performing reliable and unbiased audits.