A block of mass \(m\) is released from rest at \(x = 0\) and moves along the positive \(x\)-axis to \(x = D\). A forward force of magnitude \(F(x) = F_0\left(1 - \dfrac{x}{D}\right)\) acts on the block, while a drag force of magnitude \(F_d = bv^2\) opposes the motion, where \(b\) and \(F_0\) are positive constants. Which of the following best describes the shape of the graph of the block's kinetic energy \(K\) as a function of position \(x\) on the interval \(0 \le x \le D\)?