A metal bar is positioned inside a current-carrying coil, as shown in diagram 1. The coil has a small current. The bar supports a few nails, as shown in diagram 2. If there is no current in the coil, the nails fall off. Which row gives the correct answer?
- Asoft iron; it makes no difference
- Bsoft iron; the bar holds more nails
- Csteel; it makes no difference
- Dsteel; the bar holds more nails