When a mold fills with sand or mud and then hardens a what is formed

Which of the following is an accurate description of the recent political history of the democratic republic of the congo? a. religious tensions have escalated into full-scale civil war a number of times since the belgians left the country in 1960. b. the political leader who gained power after the overthrow of a corrupt dictator was assassinated. c. the military leadership felt the country was stable enough, so they permitted democratic elections to take place. d. in 1990, a dictator seized and has held power ever since.