the electrostatic force between the top and bottom of this thundercloud is 1) undetermined 2) repulsive 3) zero 4) attractive

attractive.

Thunder cloud is made up of charge that occurs due to friction of atmospheric conditions

Many particles of the atmosphere moves at high speed and all these motion the thundercloud get charge

Here this charge is negative and high with respect to the ground

Due to this high voltage difference occurs and it will make breakdown of atmospheric gases

So here charge on thundercloud will be same and hence it will exert repulsion force on each other

so correct answer will be

2) Repulsive