Which CHAP authentication mechanisms are only available when using software and dependent hardware i

Which CHAP authentication mechanisms are only available when using software and dependent hardware iSCSI adapters (Choose Two)?

A.
Mutual CHAP

B.
Per-Subnet CHAP

C.
Per-target CHAP

D.
One-way CHAP

Explanation:
From http://pubs.vmware.com/vsphere-50/index.jsp?topic=/com.vmware.vsphere.storage.doc_50/GUID-3F97FB05-3C92-4040-84E7-D928555B3808.html

ESXi supports the following CHAP authentication methods:

One-way CHAP
In one-way CHAP authentication, also called unidirectional, the target authenticates the initiator, but the initiator does not authenticate the target.

Mutual CHAP
In mutual CHAP authentication, also called bidirectional, an additional level of security enables the initiator to authenticate the target. VMware supports this method for software and dependent hardware iSCSI adapters only.