The capacitance of 0-1000V electrostatic voltmeter increases from 36-42 pF from zero to full scale deflection. It is required to extend the range of voltmeter to 10000 V by using an external series capacitor. What should be the value of series capacitor?

(A) 0.8 pF (B) 1.00 pF (C) 6.644 pF (D) 4.667 pF