What is the primary purpose of AWS Certificate Manager (ACM)?

The primary purpose of AWS Certificate Manager (ACM) is to provision, manage, and deploy SSL/TLS certificates. This service simplifies the process of obtaining and deploying certificates that secure network communications and establish the identity of websites over the internet. By using ACM, clients can easily request a certificate from their AWS account, manage the lifecycle of these certificates (including renewal), and deploy them with services such as Elastic Load Balancing, Amazon CloudFront, and Amazon API Gateway. This functionality is crucial for ensuring secure communications over the web, leading to safer user experiences and protection of sensitive data.

Other options, while related to security and management in AWS environments, do not align directly with ACM's core functionality. For instance, managing network traffic across multiple AWS accounts is more in the domain of services like AWS Transit Gateway or Route 53. Protecting against DDoS attacks typically falls under AWS Shield and AWS WAF (Web Application Firewall). Monitoring AWS environments for security threats is a responsibility handled by services like Amazon GuardDuty or AWS CloudTrail. Thus, the role of ACM as a certificate management service distinctly focuses on SSL/TLS certificates, making it the correct answer.