Question

http://prntscr.com/6vsng6

Answer 1

@Hoslos

Answer 2

To make yourself easier to understand, look for the variable that seems to depend on the other. That will be the dependent variable/vertical axis. And the remaining one, independent variable/x-axis.
According to this problem, I bet you can realize that it is the gas that depends on the speed the driver is driving. For instance: If you drive too fast, you waste more gas. Not if you waste more gas you drive faster. Therefore, given that gas depends on speed, the first will be the dependent variable and the latter, independent.
Answer, B.

Answer 3

thanks

Answer 4

Right.