AWS Certified SysOps Administrator SOA-C01 – Question834

A company has a business application hosted on Amazon EC2 instances behind an Application Load Balancer. Amazon CloudWatch metrics show that the CPU utilization on the EC2 instances is very high. There are also reports from users that receive HTTP 503 and 504 errors when they try to connect to the application.
Which action will resolve these issues?

A.
Place the EC2 instances into an AWS Auto Scaling group.
B. Configure the ALB's Target Group to use more frequent health checks.
C. Enable sticky sessions on the Application Load Balancer.
D. Increase the idle timeout setting of the Application Load Balancer.