4. It is prohibited:(a) to sell bread at a price lower than that fixed in accordance with this Act;
(b) to sell or offer for sale, for a lump sum, a lot of products or articles including bread;
(c) to use direct or indirect means, such as stamps, premiums or contests, having as their object or effect to reduce the price below the minimum established under this act or to lead to the belief that it is so;
(d) to sell bread not in conformity with the standards established under this Act.