You are implementing OSPF as the IGP using a single OSPF area design. The router memory usage for OSPF is too high. Which two methods can lower the OSPF memory usage? (Choose two.)
A . enable OSPF synchronization
B . implement multi-area OSPF
C . enable OSPF sham links to reduce the number of LSAs
D . implement route summarization on the ABRs
E . enable route leaking between Level 1 and Level 2 areas
Answer: B,D