challenge: When did Indo-European peoples migrate into the territory of present-day Vojvodina?
  
  A. 4200 BC, 3300 BC, and 2800 BC
  B. 4000 BC, 3100 BC, and 2600 BC
  C. 3500 BC, 3200 BC, and 2700 BC
  D. 3000 BC, 2500 BC, and 2000 BC
  Answer: 