What is the log file that shows the keep alive packets during the debug process?

What is the log file that shows the keep alive packets during the debug process?

A.
$FWDIR/log/vpnd.elg

B.
$FWDIR/log/ikev2.xmll

C.
$FWDIR/log/ike.xmll

D.
$FWDIR/log/ike.elg