Who appoints the auditor for a government company, and what is the time frame for this appointment?

Companies Act Section 139.Appointment of auditors: (5) Notwithstanding anything contained in sub-section (1), in the case of a Government company or any other company owned or controlled, directly or indirectly, by the Central Government, or by any State Government or Governments, or partly by the Central Government and partly by one or more State Governments, the Comptroller and Auditor-General of India shall, in respect of a financial year, appoint an auditor duly qualified to be appointed as an auditor of companies under this Act, within a period of one hundred and eighty days from the commencement of the financial year, who shall hold office till the conclusion of the annual general meeting.