Answer:
C. The brain has a natural tendency to generate them.
Step-by-step explanation:
Concepts often come to mind because the human brain has a natural ability to generate thoughts, ideas, and associations based on prior knowledge and experiences. This cognitive process is a fundamental aspect of human thinking and creativity. While concepts are not always stored in long-term memory (option A), and they can certainly be associated with strong emotional experiences (option B), the generation of concepts is an inherent cognitive process. Option D, stating that concepts are inaccessible in memory, is not accurate because concepts are typically accessible to varying degrees in memory, depending on factors such as how often they have been used or encountered.