In the figure shown, the capacitor is initially uncharged. Which one of the following expressions describes the current $I(t)$ (in mA) for $t > 0$?
- $I(t)= \frac{5}{3}(1-e^{-t/ \tau}), \tau= \frac{2}{3} \text{msec} \\$
- $I(t)= \frac{5}{2}(1-e^{-t/\tau}), \tau= \frac{2}{3} \text{msec} \\$
- $I(t)= \frac{5}{3}(1-e^{-t/\tau}), \tau= 3 \text{msec} \\$
- $I(t)= \frac{5}{2}(1-e^{-t/\tau}), \tau= 3 \text{msec}$