Exam 300-101 topic 1 question 844 discussion

Correct is B Summarization on ASBRs Summarization can also be performed for external routes, as illustrated in Figure 3-27. Each route that is redistributed into OSPF from other protocols is advertised individually with an external LSA. To reduce the size of the OSPF LSDB, you can configure a summary for external routes. Summarization of external routes can be done on the ASBR for type 5 LSAs (redistributed routes) before injecting them into the OSPF domain. Without summarization, all the redistributed external prefixes from external autonomous systems are passed into the OSPF area. A summary route to Null0 is created automatically for each summary range. The ASBR will summarize external routes before injecting them into the OSPF domain as type 5 external LSAs. Table 3-4 shows the parameters used with the summary-address command. To remove a the summarization, use the no form of this command http://www.ciscopress.com/articles/article.asp?p=2294214&seqNum=3

We are talking about redistributed routes. So we'are talking about redistribution that is made in ASBR..so the right command is summary-address

I thought D is correct

B “The summary-address subcommand defines the summary route on the ASBR, with similar syntax and parameters as compared to the area range command seen on ABRs.” Excerpt From: Kevin Wallace. “CCNP Routing and Switching ROUTE 300-101 Official Cert Guide.” iBooks.