A web application runs on Amazon EC2 instances behind an Elastic Load Balancing Application Load Balancer (ALB). The instances run in an Auto Scaling group across multiple Availability Zones. A SysOps Administrator has notice that some EC2 instances show up healthy in the Auto Scaling console but show up as unhealthy in the ALB target console. What could be the issue?

A. The health check grace period for the Auto Scaling group is set too low; increase it
B. The target group health check is incorrectly configured and needs to be adjusted
C. The user data or AMI used for the Auto Scaling group launch configuration is incorrect
D. The Auto Scaling group health check type is based on EC2 instance health instead of Elastic Load Balancing health checks