An IT working capital fund established under paragraph (1) may be used, subject to the availability of appropriations, only for the following: (A) To improve, retire, or replace existing information technology systems in the covered agency to enhance cybersecurity and to improve efficiency and effectiveness. (B) To transition legacy information technology systems at the covered agency to cloud computing and other innovative platforms and technologies, including those serving more than one covered agency with common requirements. (C) To assist and support covered agency efforts to provide adequate, risk-based, and cost-effective information technology capabilities that address evolving threats to information security. (D) To reimburse funds transferred to the covered agency from the Technology Modernization Fund established under section 4, with the approval of the Chief Information Officer of the covered agency. (4) Existing funds An IT working capital fund may not be used to supplant funds provided for the operation and maintenance of any system within an appropriation for the covered agency at the time of establishment of the IT working capital fund. (5) Prioritization of funds The head of each covered agency shall prioritize funds within the IT working capital fund to be used initially for cost savings activities approved by the Chief Information Officer of the covered agency, in consultation with the Administrator of the Office of Electronic Government. The head of each covered agency may reprogram and transfer any amounts saved as a direct result of such activities for deposit into the applicable IT working capital fund, consistent with paragraph (2)(A). (6) Return of funds Any funds deposited into an IT working capital fund shall be available for obligation for three years after the last day of the fiscal year in which such funds were deposited. (7) Agency CIO responsibilities In evaluating projects to be funded from the IT working capital fund, the Chief Information Officer of the covered agency shall