Final answer:
The best middleman for James Barker's firm, which requires comprehensive management of international sales including promotion, credit, and legal matters, would be an export management company (EMC).
Step-by-step explanation:
James Barker, the marketing manager of a firm with small international sales volume, is searching for a middleman who will handle various aspects of the company's international sales. Considering the responsibilities listed - such as promotion, credit arrangements, physical handling, market research, as well as financial, patent, and licensing matters - the best choice for Mr. Barker would be option 4:
An export management company (EMC). EMCs are proficient in handling the complexities of international commerce and can act under the company's name. They have the expertise to manage all aspects of exports, making them a comprehensive solution for businesses looking to expand globally without building an in-house export department.