suders permissions
 

I have set a 0 UID for normal user to give super user access to that user but i want to restrict that user to use useradd command with -o option. That user can execute useradd but not with -o.

how to do??

This link may help you with your question. Read it and see if it does.
jdk

you must not set 0 uid for a normal user, but use sudo. the 0 uid is special and means full and unrestricted access to everything. The system does not care about the username but the uid (when checks the access right)

suders permissions
 

thanks