According to Albert Ellis, problematic emotional reactions are caused by: A. the fight-or-flight response. B. catharsis. C. catastrophic thinking. D. excessive reliance on defense mechanisms.

Albert Ellis was an American psychologist who developed Rational Emotive Behavior Therapy (REBT), a form of cognitive-behavioral therapy. REBT posits that our thoughts, emotions, and behaviors are interrelated and that irrational beliefs or thoughts can cause emotional disturbances and maladaptive behaviors.

Now that we understand the basis of Albert Ellis's theories, let's analyze each option individually: A. the fight-or-flight response - This term refers to our physiological reaction to stress. While this response can influence emotional reactions, it is not the primary cause identified by Ellis. B. catharsis - Catharsis is the release of strong emotions, often through a particular activity or experience. This concept is not central to Ellis's perspective on the cause of problematic emotional reactions. C. catastrophic thinking - Catastrophic thinking involves irrational thoughts and beliefs that exaggerate and magnify perceived dangers or problems. This option seems to be most in line with Albert Ellis's theories about the cause of emotional disturbances. D. excessive reliance on defense mechanisms - Defense mechanisms are unconscious strategies we use to protect ourselves from unpleasant emotions or thoughts. While Ellis might argue that defense mechanisms could contribute to emotional issues, he would not consider them the primary cause of problematic emotional reactions.

Based on our analysis of each option and our understanding of Albert Ellis's psychological theories, the correct answer is: C. catastrophic thinking.