Concept:This is charging by induction, where earthing removes the repelled electrons and leaves the sphere with the opposite charge.
Explanation:A negatively charged rod repels free electrons in the metal sphere.
Electrons move to the far side, leaving the near side positively charged.
When the sphere is earthed, the repelled electrons escape through the earth wire to the ground.
The positive charges cannot move, so they remain on the sphere.
After removing the rod, the sphere has lost electrons and therefore has a net positive charge.
Answer:The sphere will have a net positive charge. Option C.