(b) It is an affirmative defense to prosecution under Section 15.02 or 15.03 that under circumstances manifesting a voluntary and complete renunciation of his criminal objective the actor countermanded his solicitation or withdrew from the conspiracy before commission of the object offense and took further affirmative action that prevented the commission of the object offense.

(c) Renunciation is not voluntary if it is motivated in whole or in part:

(1) by circumstances not present or apparent at the inception of the actor's course of conduct that increase the probability of detection or apprehension or that make more difficult the accomplishment of the objective; or

(2) by a decision to postpone the criminal conduct until another time or to transfer the criminal act to another but similar objective or victim.

(d) Evidence that the defendant renounced his criminal objective by abandoning his criminal conduct, countermanding his solicitation, or withdrawing from the conspiracy before the criminal offense was committed and made substantial effort to prevent the commission of the object offense shall be admissible as mitigation at the hearing on punishment if he has been found guilty of criminal attempt, criminal solicitation, or criminal conspiracy; and in the event of a finding of renunciation under this subsection, the punishment shall be one grade lower than that provided for the offense committed.