A system administrator wants to provide balance between the security of a wireless network and usability. The administrator is concerned with wireless encryption compatibility of older devices used by some employees. Which of the following would provide strong security and backward compatibility when accessing the wireless network?
A. Open wireless network and SSL VPN
B. WPA using a preshared key
C. WPA2 using a RADIUS back-end for 802.1x authentication
D. WEP with a 40-bit key