Jada fills the bathtub before taking a bath and then allows the water to drain when she is done. The graph below models the number of gallons of water, y, in the bathtub over time, t, in minutes. On a graph, the graph increases, remains constant, and then decreases.

Is the number of gallons of water in the bathtub a function of time?
Yes because each t value is paired with exactly one number of gallons.
Yes because the number of gallons is bounded between y = 0 and y = 36.
No because each number of gallons is paired with more than one t value.
No because from t = 5 to t = 20 the number of gallons of water is constant.