Subpart C of this part has discussed the various criteria for determining coverage under the Act of employers and employees in enterprises and establishments that make retail sales of goods and services. This subpart deals primarily with the exemptions from the Act's minimum wage and overtime provisions found in section 13(a) (2), (4), (11), and 13(b)(18) for employees of retail or service establishments. Also discussed are some exemptions for special categories of establishments engaged in retailing goods or services, which do not require for exemption that the particular establishment be a retail or service establishment as defined in the Act. If all the requirements set forth in any of these exemptions are met, to the extent provided therein the employer is relieved from complying with the minimum wage and/or overtime provisions of the Act even though his employees are engaged in interstate or foreign commerce or in the production of goods for such commerce or employed in covered enterprises.