Which body acts as a significant contributor to the development of GAAP?

The correct choice identifies the American Institute of Certified Public Accountants (AICPA) as a significant contributor to the development of Generally Accepted Accounting Principles (GAAP). The AICPA plays a crucial role in establishing and promoting high standards for accounting practices in the United States. It develops standards and guidelines for accounting practices, which are essential for ensuring transparency and consistency in financial reporting.

The AICPA was instrumental in the creation of accounting standards prior to the establishment of the Financial Accounting Standards Board (FASB) in 1973, which is now the primary body for setting GAAP. The initiatives taken by the AICPA, including the codification of accounting principles and the development of industry-specific guidelines, have helped shape the framework of accounting standards that are widely followed today.

In contrast, while other organizations like the FASB and SEC also play important roles in the accounting framework, it is the AICPA that has historically contributed to the foundational aspects and the evolution of GAAP. Therefore, recognizing the AICPA's role in setting ethical standards and developing professional guidance is key to understanding its influence on GAAP formation.