Resposta correta: b. /var/log/messages
Mas realmente, a opção "mais" correta que esta seria /var/log/dmesg. Essa quetão não muito bem elaborada.
Uma boa explicação que achei foi esta:
"dmesg prints the contents of the ring buffer. This information is also sent in real time to
syslogd or
klogd, when they are running, and ends up in
/var/log/messages; when
dmesg is most useful is in capturing boot-time messages from before
syslogd and/or
klogd started, so that they will be properly logged."
E esta:
"After klogd is running, dmesg
will show only the most recent kernel messages (because the ring buffer
is a fixed size and so can only hold so much), without timestamps or
other information, while /var/log/messages will retain logs according to how logrotate is configured and include timestamping (which will be slightly inaccurate for initial boot messages because dmesg doesn't have them, so the time klogd started is used for all messages read from the kernel buffer)."
Então, dmesg realmente seria a opção correta apesar no messages também conter informação utíl sobre hardware entre outras coisas.
Bruno