Hyperledger Fabric is designed to provide a foundation for developing blockchain solutions with a modular architecture. Fabric, a project under the Hyperledger umbrella by the Linux Foundation, offers flexibility through its pluggable components, enabling enterprises to tailor blockchain networks according to their specific requirements.

Key Details:

Modular Architecture: Hyperledger Fabric supports modular plug-ins for various functions, including consensus, identity management, and privacy settings. This allows organizations to customize the blockchain to suit their operational needs.

Permissioned Network: Fabric is a permissioned blockchain, meaning that it restricts network participation to authorized entities, which is ideal for enterprise use cases that require confidentiality and controlled access.

Enterprise-Grade Features: Fabric's architecture is well-suited for complex business processes, providing features like private data collections, which allow subsets of participants to create private channels for transactions.

Thus, B. FABRIC is the correct answer, as it is specifically developed to support modular, enterprise-grade blockchain solutions.