a) Because of an erroneous conscience or a seriously doubtful conscience concerning the grave malice of a deliberate act. Thus he who erroneously believes that an action which is objectively only venially sinful is a mortal sin would commit a mortal sin if he performed that action. One would also commit a mortal sin in performing an action if he has serious doubts as to whether or not it is a mortal sin or only a venial sin, for one is obliged to solve such a doubt before performing the action.
*This reveals that one loves God so little that he doesn’t care if he is sinning mortally or not. So charity is destroyed.
e_c;13664725:
Thanks for your help. It was actually letter A that confused me. So basically it means that if a person views a mortal sin as venial and commits the action, that person is guilty of mortal sin. Is that correct?