The correct option is C In the given case, sale by A to third person is not valid as A has no title. B can recover ring from third person and such third person can recover damages from A.
Section 27 of Indian Contract Act, 1872 states, "Agreement in restraint of trade, void. Every agreement by which any one is restrained from exercising a lawful profession, trade or business of any kind, is to that extent void. Every agreement by which any one is restrained from exercising a lawful profession, trade or business of any kind, is to that extent void."