Which action will restrict the number of users logging into R3 simultaneously?

Refer to the exhibit.

Multiple users are logging into R3 via Telnet and making changes at the same time. Which action will restrict the number of users logging into R3 simultaneously?
A. Apply the session-limit command to the VTY lines.
B. Add the aaa authorization command to the global configuration.
C. Apply the access-class 175 in command on line con 0.
D. Remove all configured usernames other than the admin account.