A capacitor, initially with zero stored charge, is connected in series with a 1V (volt) battery and an unknown resistor. If the voltage on the capacitor is (1-1/e) V after 10 seconds, after 20 seconds it will be:

(1) (1-1/2e) V.

(2) (1-1/4e) V.

(3) (1-1/e ) V.

(4) (1-1/e ) V.