Final answer:
A brain scan shows which areas of the brain activate when people are engaged in various tasks, such as processing and retaining information. The correct answer is option A.
Step-by-step explanation:
Based on the article, a brain scan shows A. Which areas of the brain activate when people are engaged in various tasks. Other researchers have used brain scans, such as positron emission tomography (PET) scans, to understand how people process and retain information. For instance, in one study, the activation of different areas of the brain, like the left inferior prefrontal cortex during a semantic task, was noted. This indicates that brain scans can reveal which parts of the brain are involved when we engage in various activities, such as listening to music or performing cognitive tasks.