A lump of clay of mass \(m\) moving horizontally with speed \(v_0\) across a frictionless horizontal surface collides with a stationary cart of mass \(M\). The collision occurs over the time interval from \(t_1\) to \(t_2\), during which the clay deforms and sticks to the cart, after which both objects move together. Which of the following graphs best represents the total kinetic energy \(K\) of the two-object system as a function of time \(t\)?