Final answer:
Mental imagery is the process of conjuring up a sensory experience, while a concept is a mental category that represents a group of people, objects, or events.
Step-by-step explanation:
The correct answer is d) Mental imagery; concept. Mental imagery is the process of conjuring up a sensory experience in one's own mind, such as visualizing an image or recalling a sound. A concept, on the other hand, is a mental category that represents a group of people, objects, or events. It helps us organize and categorize information in our minds.