You are tasked with designing a new Azure environment, adhering to the security best practices outlined in the Microsoft Cloud Adoption Framework for Azure. This environment is to be structured with one subscription dedicated to shared infrastructure components and three additional subscriptions dedicated to different applications. Your responsibility is to recommend a deployment solution that incorporates the use of network security groups (NSGs), Azure Firewall, Azure Key Vault, and Azure Bastion. The recommended solution should ensure minimal deployment effort and strictly follow the security best practices stated in the Microsoft Cloud Adoption Framework for Azure. What should you include in your recommendation?