According to EMC best practices, how many metadata volumes for a VPLEX Metro configuration are required on each cluster?

According to EMC best practices, how many metadata volumes for a VPLEX Metro configuration are required on each cluster?
A . 4 Metadata volumes and 4 Metadata Backup volumes
B . 2 Metadata volumes and 1 Metadata Backup volume
C . 2 Metadata volumes and 2 Metadata Backup volumes
D . 4 Metadata Volumes and no Metadata Backup volumes

Answer: C