When attempting to access a virtual machine, an administrator is unable to login using the vSphere credentials.
What two options are probable causes of the authentication failure? (Choose two.)

A.
The vSphere credentials have not been granted permissions.

B.
The vSphere credentials are granted read-only permissions.

C.
The vSphere credentials are granted no-access permissions.

D.
The vSphere credentials are not a member of the local administrator group.

Explanation:
While the details of authentication and authorization differ between ESX/ESXi and vCenter Server, the model itself is the same for both system. It relies on

privileges, roles, and permissions.
https://pubs.vmware.com/vsphere-50/index.jsp?topic=%2Fcom.vmware.wssdk.pg.doc_50%2FPG_Ch6_Authenticate_Authorize.8.3.html