A cylindrical wire has cross-sectional area $A$ and free-electron number density $n$. The wire carries current $I$, and the free electrons move with mean drift speed $v$. A second cylindrical wire has cross-sectional area $0.5A$ and free-electron number density $2n$. In this wire, the free electrons move with mean drift speed $2v$. What current is in the second wire?
- A$0.5I$
- B$I$
- C$2I$
- D$4I$