D. Maintain required pricing criteria in custom metadata types.

Custom Metadata Types in Salesforce are designed for storing and managing reusable sets of data that can be accessed across your org. This solution offers several key advantages for implementing a custom pricing engine with the described requirements:

Flexibility and Scalability: Custom Metadata Types allow you to create records that store the pricing criteria based on state, city, and zip code. Because these are metadata, they can be deployed across environments and referenced in code, making it easy to update pricing criteria without direct code changes.

Easy to Maintain and Update: Changes to pricing criteria can be made by updating the custom metadata records without needing to modify the code that references these records. This significantly reduces the maintenance overhead and allows for quick adjustments to pricing strategies as business needs evolve.

Integration with Custom Code: Custom Metadata Types can be directly accessed via Apex, Salesforce’s programming language, allowing the custom pricing engine to dynamically retrieve and apply the correct pricing criteria based on the customer’s location. This ensures that the engine can evaluate the hierarchy of location information to decide on pricing efficiently.

Deployment and Version Control: Unlike custom objects or configuration data, custom metadata types and their records can be included in package deployments and version control systems. This makes it easier to manage changes and ensure consistency across different Salesforce environments....