Two copper wires are connected end to end and a current flows through them, as shown. Wire P has diameter $d$ and wire Q has diameter $2d$. What is the ratio $\displaystyle \frac{\text{average drift speed of the free electrons in wire P}}{\text{average drift speed of the free electrons in wire Q}}$?
- A$\frac{1}{4}$
- B$\frac{1}{2}$
- C2
- D4