Final answer:
Expulsion refers to the act of being removed or forced out, which in the context of Michael’s situation, would be his removal from school. Thus, the correct definition of expulsion is option (d).
Step-by-step explanation:
Based on the understanding of word roots and prefixes, the correct definition of expulsion in the context of the sentence 'Michael’s parents avoided telling any of their friends about his expulsion from school' is most likely an instance of being removed or forced out.
This definition aligns with the notion of expulsion that refers to a dominant group forcing a subordinate group to leave a certain area or country, as historically exemplified by events such as the Trail of Tears, the Holocaust, and the internment of Japanese Americans during World War II under Executive Order 9066.
In modern educational settings, expulsion often means a student being officially removed from an institution as a disciplinary action. Therefore, the correct option is (d) An instance of being removed or forced out.