Final answer:
Product labels are designed to help consumers know what products they're buying, ensuring transparency and trust. While SSL certificates, QR codes, and watermarks also play roles in consumer confidence, product labels offer the most direct information about the product itself.
Step-by-step explanation:
Among the options provided, the one that exists to help consumers know what products they're buying is B) Product labels. Product labels contain vital information including ingredients, manufacturing details, usage instructions, and often a barcode or QR code that can be scanned for more information. This transparency is a form of assurance to consumers about what they're purchasing. Other tools like SSL certificates, QR codes, and watermarks also contribute to consumer confidence, albeit in different contexts. SSL certificates ensure safe online transactions, QR codes can link to additional product information, and watermarks help verify authenticity.
Sellers can address concerns arising from imperfect information by providing comprehensive product details, showcasing third-party certifications or endorsements, offering money-back guarantees, and maintaining a clear, responsive customer service line. By doing so, they create an environment of trust essential for a positive buyer experience.