Answer:
C) 78%
Explanation:
You can use process of elimination for this one. So first, obviously it wont be lower than the last test score which is at 65%, so you can mark off A and B. Then, if you notice the test scores fall right next to the big blue line, so find 9 hours, and then look all the way up to where it touches the line and you can see it is about a little less than 80%, which can mean that it obviously ain't D, so it is therefore C. I hope this helps :)