What is not an indication for suction-effective complete dentures is （ ）

A、Thearchrelationshipisindiscrepancyandthejawrelationisunstable.
B、Thealveolarridgeisinsevereatrophy,andthelocationofthebordersealingareacannotbedetermined
C、Ordinarydentureshaveinsufficientsuctionforce
D、Thebiteisdifficulttoadjust