Which of the Following Students Is Demonstrating an External Achievement

Which of the following students is demonstrating an external achievement attribution?

A) Hippolytos, who believes he got a good grade on the math test because he studied very hard.
B) Damaris, who believes that she got a good grade on the math test because she got lucky when answering most of the questions.
C) Zeno, who believes that he failed the math test because he was playing video games instead of studying.
D) Theodora, who believes that she failed the math test because she was trying to study while text messaging a friend about her upcoming date with Hippolytos.