Answer:
If we are investigating login issues then we have to start with 'security logs' in 'windows logs' portion of Event viewer.
Step-by-step explanation:
Much information about login issues is contained in log files which are related to security because it is mostly security issue. Some it is also better to start with 'system logs' portion of windows logs portion of Event viewer when there may be system problems instead of security issues. But in most cases there is security issues so 'security logs' is better option overall