Final answer:
The second stage of role-taking, known as the 'play stage,' is exemplified by Mary dressing up and pretending to be a doctor, as it reflects her ability to embody and understand another person's role.
Step-by-step explanation:
An example of the second stage of role-taking, often referred to as the 'play stage,' is Mary dressing up in a white coat and pretending to be a doctor. This stage, central to the theories of sociologist George Herbert Mead, is where children begin to take on the role that one other person might have. During the play stage, children act out behaviors they see in adults and start understanding the perspective of other individuals. For example, they may engage in activities such as pretending to be a parent, or in Mary's case, a doctor, which involves imitating not only the actions but also the attitudes associated with that role.