Which of the following would be an internal cause for making a good grade on the psychology test?

The correct answer is: An individual thinking "I'm smart".

Explanation:

In psychology, internal causes can be defined as the perception that individuals have about their behavior is due to personal and internal characteristics rather than by external causes and/or events.

For instance:

James scored 4 goals on his Sunday soccer match when asked about the goals he said that it was because he practices soccer every day and he tries to be the best at the game.

He considers himself to be very good at soccer and that's why he scored 4 goals in a single match which shows an internal cause.

In this particular case, an internal cause for making a good grade on a psychology test can be that the individual who got the good grade thinks that he is smart.