A block of mass \(m\) on a frictionless horizontal surface is connected to a rigid wall by an ideal spring of spring constant \(k\). An external driving force \(F(t) = F_0 \cos(\omega t)\) is applied to the block, where \(F_0\) and \(\omega\) are positive constants. The differential equation governing the motion of the block is \(m \dfrac{d^2x}{dt^2} + kx = F_0 \cos(\omega t)\). Assuming a steady-state solution of the form \(x(t) = A \cos(\omega t)\), where \(\omega \ne \sqrt{\dfrac{k}{m}}\), which of the following expressions represents the steady-state amplitude \(A\) of the oscillation?