A particle of mass \(m\) moves in one dimension along the positive \(x\)-axis. The magnitude of the particle's linear momentum as a function of position \(x\) is given by \(p(x) = C x^2\), where \(C\) is a positive constant with appropriate units. Which of the following expressions represents the magnitude of the net force \(F(x)\) acting on the particle as a function of position \(x\)?