Answer: Draw a line through the two points (0,2) and (3,3). See the attached image below.
How did I get these two points? The first point comes from the fact that "at the start, the height is 2 inches" meaning that x = 0 hours and y = 2 inches pair up together. This is show as point A. This is the y intercept as this is the location where the blue graph crosses the vertical y axis.
Point B is found by moving 1 unit up from point A and 3 units to the right to land on (3,3). So we have x = 3 hours and y = 3 inches pair up together.
Note: the slope is rise/run = 1/3 helping us determine the unit rate or speed in which the water is rising (ie the water is rising one-third of an inch per hour)