You need to ensure that users can receive reports by email according to their preferences

You are designing a subscription strategy for a SQL Server Reporting Services (SSRS)
report.
You have an application that populates a table with user-specific subscription schedules and
report formats.
You need to ensure that users can receive reports by email according to their preferences.
Email messages will be sent via an internal mail server.
What should you do? (More than one answer choice may achieve the goal. Select the BEST
answer.)

A.
Create a standard SSRS subscription for each record in the table.

B.
Create a data-driven SSRS subscription for each record in the schedule table.

C.
Create a standard SSRS subscription for each subscription schedule.

D.
Create one data-driven SSRS subscription. Schedule the subscription to frequently
retrieve user preferences.

Explanation:
http://technet.microsoft.com/en-us/library/ms187066(v=sql.105).aspx