The correct answer is D) All of the above are true.
In the following examples, the ones that are experiencing downward social mobility in the United States are Apone, Enyeto, and Senaka.
The term social mobility is a concept that refers to the change of the social class in America due to many reasons such as being promoted in your job, the change of profession, opening a new business, marrying to a son/daughter of a prominent family, being accepted into a special or elite club.
The other options of the question were A) Apone, a lawyer, has decided to quit her law practice to become an elementary school teacher. B) Enyeto, a member of Congress, has decided to retire and return to his family farm. B) Senaka, a member of a wealthy family, is now the first person in his family not to go to college.