The correct answer is Ensuring services are highly available by distributing traffic. Cloud Load Balancing in GCP is designed to distribute incoming traffic across multiple instances or backends, thereby ensuring that your applications and services are highly available and can efficiently manage increased traffic loads. This not only improves the performance and reliability of your applications but also contributes to a better user experience.

While Automatic scaling of virtual machines is a related benefit, it is not the primary function of Cloud Load Balancing. Similarly, Enhanced network security measures and Optimization of operational costs without manual intervention are valuable outcomes but are secondary to the main goal of providing high availability through traffic distribution.