; (2) how the Department of Defense prioritizes aerial refueling capabilities in support of the Saudi-led coalition; (3) the manner and extent to which the United States has been reimbursed for aerial refueling support of Saudi-led coalition aircraft; (4) whether and how the Department of Defense determines the extent to which its advice and assistance has reduced civilian casualties and damage to civilian infrastructure, including evaluating a differentiation between dynamic and deliberate targeting by the Saudi-led coalition; (5) whether and how the Department of Defense determines the efficacy of defensive advice and assistance to the Saudi-led coalition, including with respect to ballistic missiles and other threats to the sovereignty of regional partners; and (6) the responsiveness, completeness, and accuracy of any certifications submitted pursuant to section 1290 of the John S. McCain National Defense Authorization Act for Fiscal Year 2019 ( Public Law 115–232 ). (b) Briefing Not later than 180 days after the date of the enactment of this Act, the Comptroller General of the United States shall provide the preliminary results of the review conducted under subsection (a) to— (1) the Committee on Armed Services of the Senate ; (2) the Committee on Foreign Relations of the Senate ; (3) the Committee on Armed Services of the House of Representatives