Abel, a cloud architect, uses container technology to deploy applications/software including all its dependencies, such as libraries and configuration files, binaries, and other resources that run independently from other processes in the cloud environment. For the containerization of applications, he follows the five- tier container technology architecture. Currently, Abel is verifying and validating image contents, signing images, and sending them to the registries.
Which of the following tiers of the container technology architecture is Abel currently working in?

A. Tier-1: Developer machines
B. Tier-2: Testing and accreditation systems
C. Tier-3: Registries
D. Tier-4: Orchestrators