After 4 months of living in her dorm room, Molly had 5 fish. Eight months later, Molly still had 5 fish. Which of the graphs below models Molly's fish population? graph of line going through 5, 0 and 5, 8 graph of line going through 1, 6 and 4, 9 graph of line going through 0, 5 and 7, 5 graph of line going through 5, 0 and 7, 2

We can assume the x value is time, and the y-value is fish population.

The best answer is the third option, a line going through 0,5 and 7,5. We don't know if Molly arrived at the dorm with fish, but we know that during the 8 months, her fish population stayed the same at 5 fish. 

The first option features a y value of 8, so we know that's wrong. She never had more than 5 fish.
The second option is wrong for the same reason (y values of 6 and 9)
The fourth option in wrong because the fish population did not fall to 2 after 7 months.