Answer:
a. identity achievement
Explanation:
According to Marcia's theory on identity status, "identity achievement" is the status that an adolescent chose and made a commitment to a sense of identity (which can be a role or a value, a job that they want) after he/ she has already gone through much experience, attempt and exploration, even crisis before.
In this case, Heidi despite being from the upper-middle-class, she has already spent time exploring the new environment, experienced jobs that is different from her social class and from these experiences, she understands herself and has clear objectives in the future.
Meanwhile:
+) foreclosure: they commit to a role but not having any experience, crisis, this is tend to comfort the other people's expectation
+) role confusion: have not had clear choice
+) moratorium: the status that still in crisis and exploration of role, value want to commit to
=> All these three are different from the case of Heidi.
