A Company Is Running a Website on Amazon EC2 Instances

A company is running a website on Amazon EC2 instances behind an Application Load Balancer (ALB) . The company configured an Amazon CloudFront distribution and set the ALB as the origin. The company created an Amazon Route 53 CNAME record to send all traffic through the CloudFront distribution. As an unintended side effect, mobile users are now being served the desktop version of the website. Which action should a SysOps administrator take to resolve this issue?

A) Configure the CloudFront distribution behavior to forward the User-Agent header.
B) Configure the CloudFront distribution origin settings. Add a User-Agent header to the list of origin custom headers.
C) Enable IPv6 on the ALB. Update the CloudFront distribution origin settings to use the dualstack endpoint.
D) Enable IPv6 on the CloudFront distribution. Update the Route 53 record to use the dualstack endpoint.