Which user ID must be locked for security reasons after you create an administrator business user?

Which user ID must be locked for security reasons after you create an administrator business user?
A . SAP Lifecycle Management Administrator (SAP_LMADM)
B . SAP Customer Business User (SAP_CUST_BUS)
C . SAP Customer Initial User (SAP_CUST_INI)
D . SAP E-Mail Inbound Processing (SAP_SMTP_IN)

Answer: C