A student conducts an experiment to determine the constant acceleration \(a\) of a cart that starts from rest and rolls down a long, straight incline. Using a motion sensor, the student records the cart's position \(x\) at several different times \(t\). The cart is at position \(x = 0\) at time \(t = 0\). Which of the following pairs of quantities, when plotted on the vertical and horizontal axes respectively, will produce a linear graph that can be used to determine the acceleration of the cart?