\( -1 \times 10^{-6} C \) charge is on a drop of water having mass \( 10^{-6} kg \). What electric field should be applied on the drop so that it is in the balanced condition with its weight?
a) \( 10 V / m \) upward
b) \( 10 V / m \) downward
c) \( 0.1 V / m \) downward
d) \( 0.1 V / m \) upward