Which approach should you recommend?

You are designing a SharePoint 2010 application that connects to an external Microsoft SQL Server database.
You have the following requirements:
Server administrators can add and edit connection strings at the Web application level.
.SharePoint users must not be able to view or modify sensitive data in the connection strings.
.Server administrators can add or change the connection strings declaratively with no custom UI required.
.The connection strings can be modified programmatically without redeploying code.
You need to create a plan to store connection strings for the database within the SharePoint system.
Which approach should you recommend?

A.
Add or change the connection strings in the web.config file.

B.
Use a hierarchical object store configuration approach to store the connection strings.

C.
Use a property bag configuration approach to store the connection strings.

D.
Use SharePoint lists to store the connection strings.