(a) In any case not extending to the dismissal of a commissioned officer, the sworn testimony, contained in the duly authenticated record of proceedings of a court of inquiry, of a person whose oral testimony cannot be obtained may, if otherwise admissible under the rules of evidence, be read in evidence by any party before a court-martial if the accused was a party before the court of inquiry and had the opportunity to cross-examine the witness and if the same issue was involved or if the accused consents to the introduction of the evidence.
(b) This testimony may be read in evidence only by the defense in cases extending to the dismissal of a commissioned officer.
(c) This testimony may also be read in evidence before a court of inquiry or a military board.