以下哪个是DFDS的正确后缀树

Models drawn by the system analysts during the process of the structured analysis are（）. A: PERTs B: EMV C: UMLs D: DFDs

Models drawn by the system analysts during the process of the structured analysis are（） A: PERTs B: ERDs C: UMLs D: DFDs

Models drawn by the system analysts during the process of the structun:d analysis are ______. A: PERTs B: ERDs C: UMLs D: DFDs

Models drawn by the system analysts during the process of the structured analysis are （75） . A: PERTs B: ERDs C: UMLs D: DFDs