How can you notify suppliers to register on the Ariba Network?

How can you notify suppliers to register on the Ariba Network?
A . Send invitations to the supplier users via SAP Ariba Discovery
B . Generate password for supplier user in Ariba
C . Send an email to the supplier users via the message board
D . Bulk upload the suppliers users through enablement workbook
E . Invite supplier users through sourcing event

Answer: B,D,E