Smythe was charged with the murder of his wife. In his defense, he testified that at the time he killed her, he believed that his wife was planning to destroy the world by detonating a massive explosive device that she had developed and built in the basement of their home. He further testified that he had tried many times to dissuade his wife from her plan and had tried to destroy devices that she stored in the basement. She had, he testified, foiled his efforts by on two occasions signing papers for his hospitalization, which lasted for a brief period each time. He said that he had concluded that the only way to prevent her scheme was to kill her and that he had become so obsessed with the importance of doing so that he could think of nothing else. One day when he saw her open the door to the basement he lunged at her and pushed her down the steps to her death. The best defense raised by Smythe's testimony is
lack of the requisite mental element. lack of the requisite act element. insanity. belief that the situation justified his actions