(a) To determine the extent and source of actual damages and to mitigate exemplary damages, the defendant in a libel action may give evidence of the following matters if they have been specially pleaded:
(1) all material facts and circumstances surrounding the claim for damages and defenses to the claim;
(2) all facts and circumstances under which the libelous publication was made; and
(3) any public apology, correction, or retraction of the libelous matter made and published by the defendant.
(b) To mitigate exemplary damages, the defendant in a libel action may give evidence of the intention with which the libelous publication was made if the matter has been specially pleaded.