Q:Given the following passage  "Idris' government was increasingly unpopular by the latter 1960s; it had exacerbated Libya's traditional regional and tribal divisions by centralising the country's federal system in order to take advantage of the country's oil wealth, while corruption and entrenched systems of patronage were widespread throughout the oil industry. Arab nationalism was increasingly popular, and protests flared up following Egypt's 1967 defeat in the Six-Day War with Israel; allied to the western powers, Idris' administration was seen as pro-Israeli. Anti-western riots broke out in Tripoli and Benghazi, while Libyan workers shut down oil terminals in solidarity with Egypt. By 1969, the U.S. Central Intelligence Agency was expecting segments of Libya's armed forces to launch a coup. Although claims have been made that they knew of Gaddafi's Free Officers Movement, they have since claimed ignorance, stating that they were monitoring Abdul Aziz Shalhi's Black Boots revolutionary group.",  answer the following question. Note that the answer is present within the text.  Question: Which of the following is not a type of division in Libya: regional, entrenched, or tribal?
A:
entrenched