单项选择题A Cisco Aironet 1020 controller-based access point has been connected to a Catalyst 3550-24PWR Switch. However, when it is powered up, the access point fails. What has caused this problem?()
A.access point does not support 802.11h
B.incorrect switch power supply
C.switch port is not enabled
D.switch does not support 802.3af
E.access point has not been initialized with the primary controller