Final answer:
If the suspended pith ball moves away from the approaching negatively charged polythene strip, we can conclude that the charge on the pith ball is positive.
Step-by-step explanation:
If the suspended pith ball moves away from the approaching negatively charged polythene strip, we can conclude that the charge on the pith ball is positive. This is because opposite charges attract each other, so the negative charge on the polythene strip is attracting the positive charge on the pith ball, causing it to move away.