Choice "C" is correct. A single audit represents a combined audit of both an entity's financial statements and federal financial assistance programs. The single audit provides audited organizations with the opportunity to capitalize on the efficiency of satisfying their audit requirements with a single audit. Auditors are governed by the Single Audit Act and OMB Circular A-133.
Choice "d" is incorrect. A single audit is not simply an audit of federal financial assistance.
Choice "a" is incorrect. A single audit is not simply an audit of federal financial assistance.
Choice "b" is incorrect. A single audit is not limited to expression of an opinion on the fair presentation of financial statements. It also is designed to report on compliance with laws, rules, and regulations.