“producer”, in relation to a product, means—
(a) the person who manufactured it;
(b) in the case of a substance which is not manufactured but
is won or abstracted, the person who won or abstracted
it;
(c) in the case of a product which is not manufactured, won
or abstracted but the essential characteristics of which
are attributable to an industrial or other process having
been carried out, the person who carried out that process;