Here's a problem to solve: Mr. Jenkins constructed a circuit consisting of a variable source, wires, and a resistor. In order to triple the amount of current, how should he change the voltage of the source?

Among the 4 following options, which is the correct answer?

- A: make the voltage three times larger
 
- B: make the voltage one-third as great
 
- C: make the voltage nine times larger
 
- D: make the voltage one-ninth as great
 