What is a challenge of the SaaS model?

Refer to the exhibit. A customer is planning to onboard three new VPN partner connections in the data center. The new subnets must not overlap with the existing data center network, and the subnet size must not be bigger than necessary. The customer dedicated 10.1.8.0/21 for this design. Ho 1 // must the subnets be divided to meet these requirements?
A)

B)

C)

D)

Exhibit:

Which feature provides the capability for intra-VN traffic filtering and control within the Cisco SO-Access architecture?