This Convention does not apply to sales:
(a) of goods bought for personal, family or household use, unless the seller, at any time before or at the conclusion of the contract, neither knew nor ought to have known that the goods were bought for any such use;
(b) by auction;
(c) on execution or otherwise by authority of law;
(d) of stocks, shares, investment securities, negotiable instruments or money;
(e) of ships, vessels, hovercraft or aircraft;
(f) of electricity.