The file /etc/ssh_known_hosts typically contains hosts keys for ______.

A.
all hosts that have logged into this server via ssh

B.
all hosts that users have logged into from this server via ssh

C.
clients allowed to connect to this host via ssh

D.
machines the system administrator trusts users to connect to using ssh

Explanation/Reference:
From the man pages:
/etc/ssh/ssh_known_hosts    Systemwide list of known host keys. This file should be prepared by the system administrator to contain the public host keys of all machines in the organization. It should be world-readable.