What type of audit was conducted by auditors reviewing claims over a specific timeframe?

The correct choice reflects the nature of a comprehensive audit, which typically involves a thorough examination of an entire set of claims or records over a specified period. This type of audit is designed to evaluate the overall compliance and accuracy of claims, examining all relevant documentation and processes in detail.

A comprehensive audit provides insights into systemic issues, policy adherence, and areas of potential improvement within the organization's billing practices and compliance strategies. This depth of analysis allows organizations to ensure that their claims are being submitted accurately and in compliance with relevant regulations, which is essential for maintaining the integrity of healthcare reimbursement processes.

In contrast, the other options refer to different audit approaches. A sampling audit would only review a select number of claims rather than all claims over the specified timeframe. An external audit typically involves an independent auditor outside the organization evaluating the practices and processes, and a concurrent audit focuses on real-time analysis of claims as they are being processed. Each of these alternatives serves a distinct purpose but does not encompass the comprehensive nature of the selected answer.