Stephan noticed that his heart pounded and his palms were sweaty when he encountered a bear in the woods and when he kissed his girlfriend for the first time. He felt afraid when he saw the bear because it was a threatening situation, but he felt excited with the kiss. Which theory of emotion best explains Stephan's emotions?

A)the James-Lange theory
B)the spillover effect
C)the Cannon-Bard theory
D)the two-factor theory