If the 2- $\mu$ F Capacitor in the Circuit Shown Initially Had a Potential

Multiple Choice

If the 2- $\mu$ F capacitor in the circuit shown initially had a potential difference of 10 V across its plates,how much charge is left on it after the switch has been closed for a duration equal to one half of the time constant?

A) 12.1 µC
B) 20 µC
C) 7.9 µC
D) 0.08 µC