Stop memorizing OSPF tables: test your mental model
Can you instantly picture the boundary router LSAs without looking at a cheat sheet? Drop your answer in the comments!
The question
Which LSA is generated by an ABR to tell other areas how to reach an ASBR?
The answer
B Type 4 (ASBR Summary LSA)
Type five injects the external routes, but Type four is the ABR's signpost pointing back to that ASBR. Don't confuse it with Type three summary networks. Follow for tomorrow's rep.
Exam tip
Read what the question is actually asking before looking at the options. The wrong answers here are ones candidates genuinely pick — each is true of something adjacent, just not of what was asked.