You are setting up multinode HA for redundancy.
AnswerA, C
ExplanationComprehensive Detailed Step-by-Step Explanation with All Juniper Security Reference
Understanding Multinode HA:
Chassis Cluster in Active/Passive Mode:
One node is active, and the other is standby.
Dynamic Routing Protocols:
Run on the active node only.
Option A: Dynamic routing is active on one device at a time.
In active/passive HA, dynamic routing protocols run only on the primary (active) node.
'In a chassis cluster, the primary node handles all control plane tasks, including dynamic routing.'
Source: Juniper TechLibrary - Chassis Cluster Overview
Option C: Physical connections are used for the control and fabric links.
Control and fabric links are direct physical connections between cluster nodes.
'The control and fabric links must be connected using physical interfaces between the nodes.'
Source: Juniper TechLibrary - Chassis Cluster Components
Why Options B and D are Incorrect:
Option B: Dynamic routing is not active on both devices simultaneously in active/passive mode.
Option D: The Inter-Cluster Link (ICL) uses Layer 2 connectivity, not Layer 3.
Conclusion:
The correct options are A and C.