In the United States the governments makes collusion illegal with antitrust laws because monopolies reduce economic efficiency.
The answer is C im pretty sure Imao
Byzantium/Constantinople was conquered in 1451, but the empire continued to decline starting around the 18th or 19th centuries. It officially died in WWI. As for how long it was a major threat to Europe, the empire's prime was the 16th century, under Suleiman the Magnificent.
