Four wires are made from the same metal. Which wire would have the smallest resistance?
- Alength $20\,\text{cm}$, diameter $0.20\,\text{mm}$
- Blength $20\,\text{cm}$, diameter $0.40\,\text{mm}$
- Clength $40\,\text{cm}$, diameter $0.20\,\text{mm}$
- Dlength $40\,\text{cm}$, diameter $0.40\,\text{mm}$