(Radio) When deploying GPON Type C single-attribution protection, the following description is correct.

In Type C single-attribution protection, two PON ports form a protection pair to one ONU/ODN, but only one path is active at a time.

B — Correct: Protection groups operate in active/standby mode; only one OLT-side PON port forwards user traffic at any moment.

A — Not necessarily correct: A branch fiber break local to one path can trigger switchover, but describing it as “the OLT work port becomes standby” is imprecise; the group performs role inversion based on configured triggers and signaling, not solely by OLT port state wording.

C — Not always: Uplink failure triggers switchover only if the protection group is explicitly configured to track the uplink Ethernet port; it is not an unconditional behavior.

D — Misleading: While service entries for the ONU remain consistent from a user perspective, additional protection-group configuration is required on the OLT; thus it is not “completely identical” to a non-protected setup.

(Reference: HCIP-Access V2.5 – Type C single-homing protection architecture, active/standby forwarding, and optional uplink-tracking triggers.)