No public body shall exclude the public from any meeting to discuss any matter described in subsection 7. b. until the public body shall first adopt a resolution, at a meeting to which the public shall be admitted:

1. a. Stating the general nature of the subject to be discussed; and b. Stating as precisely as possible, the time when and the circumstances under which the discussion conducted in closed session of the public body can be disclosed to the public.

L.1975, c. 231, s. 8.