Rex did poorly on his biology exam and blames his teacher. He does not feel like she prepared him for the exam, even though he went out the night before the exam to a party, and didn't finish reading the chapters. After taking the test, he complained to his classmate that the test was unfair. Rex believes that chance, luck, and the behavior of others control his life. According to Rotter, Rex has a(n) locus of control.

External locus of control

Explanation:

In simple words, People who have an external center of authority feel that events in their life are beyond their management, meaning that sometimes their own acts are the consequence of other causes such as destiny, misfortune, the persuasion of strong outsiders (such as physicians, cops, or government leaders), and/or faith.

Thus, from the above we can conclude that the correct answer is external locus of control.