请教各位大神，感觉是同一个题再两套题库里有不同的答案，这个应该怎么选？

蔫儿不出溜儿

完全版
QUESTION 235
Using new backup router in spite of faulty one in ospf domain but relationship with neighbor in one
interface only not working , what is the reason of this problem?(choose 2)
A. area Id mismatch
B. authentication mismatch
C. process id of ospf not match
D. ospf timers not match
AD

QUESTION 542
Using new backup router in spite of faulty one in ospf domain but relationship with neighbor in one
interface only not working , what is the reason of this problem? (Choose Two)
A. area Id match
B. authentication mismatch
C. process id of ospf not match
D. ospf timers not match
E. MTU mismatch
DE

QUESTION 789
A network engineer replaced a bad router with a spare, used router in an OSPF network.
After the replacement, OSPF neighborship is not being established on one of the
interfaces. Which two reasons cause this issue? (Choose two)
A. authentication mismatch
B. MTU mismatch
C. OSPF process numbers do not match on both neighbor routers
D. OSPF timers match
E. area numbers match
BC

精简版366
QUESTION 366
A network engineer replaced a bad router with a spare, used router in an OSPF network.
After the replacement, OSPF neighborship is not being established on one of the
interfaces. Which two reasons cause this issue? (Choose two)
A. authentication mismatch
B. MTU mismatch
C. OSPF process numbers do not match on both neighbor routers.
D. OSPF timers match
E. area numbers match
Correct Answer: BC