Which of the following statements demonstrates intrinsic motivation?
a. i traveled to mexico to learn about my family's history.
c. i joined the science club to make my parents happy.
b. i work extra hours at my boring job to make extra money.
d. i study every night in order to be the best in the class.

The statement that demonstrates intrinsic motivation would be a - I traveled to Mexico to learn about my family's history. The person who would say this would imply that he's interesting in learning about what his family's history is all about and that he would be prepared to travel to another country to learn about it - this is an example of intrinsic motivation. 

The statement that best demonstrates intrinsic motivation would be : D. I study every night in order to be the best in the class

Intrinsic motivation is the kind of motivation that arise from one's inner conscience. In this case, your willingness to be the best is the voice from your inner conscience that drive you to study everynight