The author implies that one way that VHS producers won control over the VCR market was by

A、carefullyrestrictingaccesstoVCRtechnology
B、givingupaslightearlyleadinVCRsalesinordertoimprovelong-termprospects
C、retainingastrictmonopolyontheproductionofprerecordedvideotapes
D、sharingcontrolofthemarketingofVHS-formatVCR's