A liquid conductor with uniform resistivity \(\rho\) flows through a tapered pipe of length \(L\). The pipe has a circular cross-section whose radius varies with position \(x\) along the pipe as \(r(x) = R_0\left(1 - \dfrac{x}{2L}\right)\) for \(0 \le x \le L\). A steady total electric current \(I\) is maintained through the liquid along the \(x\)-axis, carried by charge carriers of charge \(q\) and uniform concentration \(n\). Which of the following correctly gives the drift speed \(v_d(L)\) of the charge carriers at \(x = L\) in terms of their initial drift speed \(v_d(0)\) at \(x = 0\), and the total potential difference \(\Delta V\) across the pipe?