A capacitor (C = 4.0 μF) is connected through a resistor (R = 2.5 MΩ) across a battery of negligible internal resistance of voltage 12 volts. The time after which the potential difference across the capacitor becomes three times to that of resistor is (ln 2 = 0.693)?

• A. 13.86 sec
• B. 6.48 sec.
• C. 3.24 sec.
• D. 20.52 sec