A customer is installing an HMC-managed Power 720 with two partitions, one for Production the other for Testing. They plan to use the Testing partition only occasionally and want to minimize hardware. Which of the following meets these requirements?（）

A. Create a system profile for each partition. Assign all needed resources as 'required'.
B. Define all system resources as 'desired' on the Testing partition. Activate only as needed.
Create two shared processor pools. Assign the minimal I/O resources required for each partition to the shared pools.
D. Create both partitions with minimal 'required' resources, and optional resources as 'desired'. Activate each partition as necessary.