Final answer:
The correct answer is option a. brand manager.
Step-by-step explanation:
Chris Carmin, who manages specific products and promotion at Birhg and Shnny toothbrush company, is likely a brand manager. This role is responsible for the development and implementation of marketing strategies for a specific brand or product line. A brand manager's goals are to increase brand awareness, develop brand strategies and marketing plans, and potentially oversee product development and market research. The responsibilities mentioned, notably managing products and promotion, align closely with the typical job description of a brand manager.
By contrast, a project manager would be concerned with planning, executing, and closing projects rather than focusing on specific products or brands. A channel manager would specialize in the strategies of distributing products across various sales channels. A sales representative focuses on selling products to customers, often without the strategic responsibilities associated with brand management.