(3) A mark shall not be registered as a trade mark if it consists exclusively of-
(a) the shape of goods which results from the nature of the goods themselves; or
(b) the shape of goods which is necessary to obtain a technical result; or
(c) the shape which gives substantial value to the goods. Explanation.- For the purposes of this section, the nature of goods or services in relation to which the trade mark is used or proposed to be used shall not be a ground for refusal of registration.