A SysOps Administrator is managing a web application that runs on Amazon EC2 instances behind an ELB Application Load Balancer (ALB). The instances run in an EC2 Auto Scaling group. The administrator wants to set an alarm for when all target instances associated with the ALB are unhealthy.
Which condition should be used with the alarm?

A. AWS/ApplicationELB HealthyHostCount <= 0
B. AWS/ApplicationELB UnhealthyHostCount >= 1
C. AWS/EC2 StatusCheckFailed <= 0
D. AWS/EC2 StatusCheckFailed >= 1