A parallel plate capacitor has a capacitance of C_0. The capacitor is then connected in series with a battery (V_0) , a resistance (R), and a switch (S). Then the switch is closed, so that the capacitor is fully charged Q. After that, the switch is opened and a dielectric material is inserted into the capacitor until the capacitance becomes 5C_0. Which of the following statements is true regarding the charge in the capacitor after the dielectric has been inserted?
a. The charge becomes 5Q
b. The charge becomes (\frac{1}{5})Q
c. The charge becomes 0,5Q
d. The charge is fixed at Q
e. The charge becomes zero