What conclusions can be drawn based on these scan results?

Firewalk has just completed the second phase (the scanning phase) and a technician receives the output
shown below. What conclusions can be drawn based on these scan results?
TCP port 21 – no response
TCP port 22 – no response
TCP port 23 – Time-to-live exceeded

A.
The firewall itself is blocking ports 21 through 23 and a service is listening on port 23 of the target host.

B.
The lack of response from ports 21 and 22 indicate that those services are not running on the destination
server.

C.
The scan on port 23 passed through the filtering device. This indicates that port 23 was not blocked at the
firewall.

D.
The scan on port 23 was able to make a connection to the destination host prompting the firewall to respond
with a TTL error.