Where the head of a government institution refuses to give access to a record requested under this Part or a part thereof, the head of the institution shall state in the notice given under paragraph 7(a):
(a) that the record does not exist, or
(b) the specific provision of this Part on which the refusal was based or, where the head of the institution does not indicate whether a record exists, the provision on which a refusal could reasonably be expected to be based if the record existed.