Which of the following is incorrect regarding the sales principles?

The statement regarding sales principles that states "People buy on logic and defend with emotion" captures a common understanding of consumer behavior in sales. It suggests that while buyers may use logical reasoning to arrive at a decision, their emotions significantly influence how they justify that choice later on. This principle highlights the dual nature of decision-making, where both logic and emotional factors are at play.

Choosing to focus on strengthening the emotional connection and engagement is a core aspect of effective selling. Customers often respond better when they feel an emotional connection to a product or service, which underscores the importance of building rapport and trust in a sales relationship.

The other statements do relate to established sales principles. Building a positive relationship with customers is critical, as people are more likely to purchase from someone they like. Similarly, being knowledgeable about your product or service builds credibility and instills confidence in the customer. Encouraging customer involvement on multiple levels can also enhance the sales experience by increasing investment in the purchasing decision. Each of these elements contributes to a more effective sales strategy, but the essence of option C highlights the nuanced complexity of buyer behavior that doesn't accurately reflect the predominant motivational drivers in sales contexts.