???? Topology Summary:

R6 has Loopback0 IP: 2000::6/128 in Area 2 (common area).

R4 is in Area 1, which is a totally stub area — it can’t receive external (Type-5) or NSSA (Type-7) LSAs, only default route (::/0).

R1 and R2 are ABRs that connect areas.

R5 and Area 3 are not relevant here because the destination (R6) is in Area 2.

???? Option A: R4 → R2 → R6

❌ False

R4 is in Area 1, and R2 is not connected to Area 1. R4 cannot reach R2 directly, so this path is invalid.

???? Option B: R4 → R1 → R5 → R3 → R6

❌ False

Although technically possible by topology, this path is not optimal and unlikely to be selected by SPF.

Also, R4 would use default routes via R1 (ABR), not route through Area 3 when shorter paths exist.

???? Option C: R4 → R1 → R3 → R6

✅ True

Valid path:

R4 (in Area 1) uses default route to R1 (ABR).

R1 forwards to R3, which connects to R6.

This is a valid and efficient OSPFv3 path.

???? Option D: R4 → R1 → R2 → R6

✅ True

Also valid:

R4 goes to R1 via default.

R1 forwards to R2 (connected to R6).

SPF may select this path depending on link costs.

Both C and D are feasible.

✅ Final Answer: C, D

Official Huawei Extract:

" In a totally stub or NSSA area, routers use default routes learned from the ABR. Forwarding decisions to external or inter-area routes are made at the ABR level (e.g., R1), and the traffic is then forwarded based on SPF calculation. "

— [Huawei HCIA-Datacom Certification Guide – OSPFv3 Area Types and Route Selection]