Three separate RC circuits—labeled I, II, and III—each use the same 4.0μF capacitor but different resistors. Circuit I has a 0.50kΩ resistor, Circuit II has a 1.0kΩ resistor, and Circuit III has a 2.0kΩ resistor. Rank the circuits from the one that reaches 63 percent of its final charge in the least time to the one that takes the most time.
a) III < II < I
b) II < I < III
c) I < II < III
d) I < III < II