challenge: What event in 2018 led to the TPLF, a predominantly Tigrayan militia, losing power in Ethiopia?
  
  A. The TPLF was defeated by a rival militia
  B. The Ethiopian government was overthrown by a foreign power
  C. The TPLF won a decisive battle against the Ethiopian government
  D. Ethnic Oromo Abiy Ahmed won the election
  Answer: 