A battery, an ammeter, a switch, a lamp and a resistor are joined in a circuit. With the switch open, the ammeter shows $2.4\,\text{A}$. After the switch is closed, the reading rises to $4.0\,\text{A}$. What is the current through the resistor when the switch is closed?
- A$0\,\text{A}$
- B$1.6\,\text{A}$
- C$3.2\,\text{A}$
- D$6.4\,\text{A}$