In order to fix this design failure, which two mechanisms can you use to isolate the data center area from the hub-and-spoke area without losing Ip connectivity?

Refer to the exhibit.

This new OSPF network has four areas, but the hub-and-spoke area experiences frequent flapping.

In order to fix this design failure, which two mechanisms can you use to isolate the data center area from the hub-and-spoke area without losing Ip connectivity? (Choose two)
A . Use OSPF distribute-list filtering on router A
B . Deploy a prefix summarization on router D
C . Make the data center area a NSSA
D . Make the data center area totally stub
E . Convert the data center area to EIGRP protocol

Answer: B,D