Exam JN0-663 topic 1 question 48 discussion

AB where the as path must be 110

shouldn't R2 set the AS-Path to 110?

A is correct and D is correct because R2 set as-path as null when receive the prefix from R1.

A and D ARE correct. R2 sets null as-path (i) when advertise the prefix to R1.

R2 should put 110 but since it's not the case, D is the answer that makes more sense, R2 will advertise null to avoid becoming transit https://www.juniper.net/documentation/us/en/software/junos/routing-policy/topics/concept/policy-configuring-as-path-regular-expressions-to-use-as-routing-policy-match-conditions.html In the following example, locally administered AS 2 is connected to AS 1 (10.2.2.6) and AS 3. AS 3 advertises its routes to AS 2, but the administrator for AS 2 does not want to advertise AS 3 routes to AS 1 and thereby allow transit traffic from AS 1 to AS 3 through AS 2. To prevent transit traffic, the export policy only-my-routes is applied to AS 1. It permits advertisement of routes from AS 2 to AS 1 but prevents advertisement of routes for AS 3 (or routes for any other connected AS) to AS 1:

Only A is correct, may be they have done some typo in Question, May be B is 110 instead of 150

Probably A,C A if peer with interface address C if peer with loopback address(multihop)

Could it be A and C? From R1, the next hop would be the R2's loopback as it's iBGP (option C) and from R2 towards R4, R2 would use the interface IP as next hop as it's eBGP (option A).

Im having a hard time justifying this question. A is absolutely correct. D however is shaky! the AS path is set to 110, not 150. but NULL?