What will be the state of the alarm at the end of 90 minutes, if the CPU utilization is constant at 80%?

A user has set up the CloudWatch alarm on the CPU utilization metric at 50%, with a time interval of 5 minutes and 10 periods to monitor.

What will be the state of the alarm at the end of 90 minutes, if the CPU utilization is constant at 80%?
A . ALERT
B . ALARM
C . OK
D . INSUFFICIENT_DATA

Answer: B

Explanation:

In this case the alarm watches a metric every 5 minutes for 10 intervals. Thus, it needs at least 50 minutes to come to the “OK” state.

Till then it will be in the INSUFFUCIENT_DATA state.

Since 90 minutes have passed and CPU utilization is at 80% constant, the state of alarm will be “ALARM”.

Reference: http://docs.aws.amazon.com/AmazonCloudWatch/latest/DeveloperGuide/AlarmThatSendsEmail.html