What gives administrators more flexibility when configuring Captive Portal instead of LDAP query for Identity Awareness authentication?

What gives administrators more flexibility when configuring Captive Portal instead of LDAP query for Identity Awareness authentication?

A.
Captive Portal is more secure than standard LDAP

B.
Captive Portal is more transparent to the user

C.
Nothing, LDAP query is required when configuring Captive Portal

D.
Captive Portal works with both configured users and guests