Rule 17.5 - Matters Not Subject to Disclosure(a)Work Product. Except as provided in Rule 17.1(a) (i) and (iv), disclosure shall not be required of research or of records, correspondence, reports or I memoranda to the extent that they contain the opinions, theories or conclusions of the prosecuting attorney or members of his staff or other state agents.(b)Informants. Disclosure shall not be required of an informant's identity where his identity is a prosecution secret and a failure to disclose will not infringe upon the constitutional rights of the defendant. This subsection shall not be construed to permit refusal to disclose the identity of witnesses to be produced at any hearing or at trial.(c)National Security. Disclosure shall not be required where it involves a substantial risk of grave prejudice to national security and a failure to disclose will not infringe upon the constitutional rights of the defendant. This subsection shall not be construed to permit refusal to disclose the identity of witnesses to be produced at any hearing or at trial.