NO$\mathrm{.}37$ A system administrator recently informed the IS auditor about the occurrence of several unsuccessful intrusion attempts from outside the organization. Which of the following is MOST effective in detecting such an intrusion?$($A$).$ Using smart cards with one$-$time passwords$($B$).$ Periodically reviewing log files$($C$).$ Configuring the router as a firewall$($D$).$ Installing biometrics$-$based authentication