Based on EMC best practice, how should the SavVol be manually sized?

A.
10% of the production file system

B.
10% of the available disk space

C.
20% of the total used space

D.
20% of the total space available

Explanation:
http://blog.e2h.net/wp-content/uploads/2014/03/R_MOD_20-VNX_SnapSure.pptx