What is one advantage of using EAP-TTLS instead of EAP-TLS as an authentication mechanism in an 802.11 WLAN?

A.
EAP-TTLS sends encrypted supplicant credentials to the authentication server, but EAP-TLS uses unencrypted user credentials.

B.
EAP-TTLS supports client certificates, but EAP-TLS does not.

C.
EAP-TTLS does not require an authentication server, but EAP-TLS does.

D.
EAP-TTLS does not require the use of a certificate for each STA as authentication credentials, but EAP-TLS does.