How does the IP access control functionality work?

How does the IP access control functionality work?
A . Users logging in from one of the IP addresses from an allowlist can log in using the registered phone number only. All other IPs are fully restricted.
B. Users logging in from one of the IP addresses from an allowlist can log in with their user name and password only. All other IPs are fully restricted.
C. Users logging in from one of the IP addresses from an allowlist can log in using the registered phone number only. All other users will need to confirm their identity via user name, password, and two-step authentication.
D. Users logging in from one of the IP addresses from an allowlist can log in with their user name and password only. Users logging in from all other IP addresses must confirm their identity via two- step authentication.

Answer: D