Which of the following organizations assists the President in overseeing the preparation of the federal budget and to supervise its administration in Executive Branch agencies?

The Office of Management and Budget (OMB) is a critical component of the Executive Office of the President, with a primary mission to assist the President in preparing the federal budget. The OMB also oversees the implementation of the budget across federal agencies and ensures compliance with presidential priorities and policies, making it the correct answer for its role in budget preparation and administration.

NIST (National Institute of Standards and Technology) is a non-regulatory federal agency that promotes U.S. innovation and industrial competitiveness, not budget oversight.

NSA/CSS (National Security Agency/Central Security Service) is a U.S. intelligence agency responsible for global monitoring and data collection for foreign intelligence, not budget management.

DCAA (Defense Contract Audit Agency) provides audit and financial advisory services to the Department of Defense, but does not oversee the entire federal budget preparation.