(a) All eggs offered for sale at retail shall be plainly marked as to grade and size with letters not less than three-eighths inch in height.

(b) All eggs advertised or displayed for sale for human food at a given price shall be advertised or displayed in the manner adopted by legislative rule.

(c) Restaurants, hotels, delicatessens and other eating places using eggs below "A" quality shall advertise this fact to the public according to legislative rule.