Refer to the exhibit. Routers P4 and P5 receive the 0.0.0.0/0 route from the ISP via eBGP peering. P4 is the primary Internet gateway router, and P5 is its backup. P5 is already advertising a…

The `default-information originate metric 100 metric-type 1` command ensures P4 advertises a default route into OSPF with a lower metric (100) than P5 (200), making it the preferred path. Since P4 already receives a default route via eBGP, the `always` keyword is not needed, preventing blackholing if the external route is lost. The `area 0 range ... not-advertise` command configures OSPF summarization to prevent specific subnets from being advertised from Area 0.

The `always` keyword would cause P4 to advertise a default route even if it loses its eBGP-learned default route, potentially leading to traffic blackholing.

Similar to B, the `always` keyword is inappropriate for a router that relies on an external default route and needs to stop advertising it if the external route disappears.

While `default-information originate` with the correct metric is present, this option omits the `area 0 range ... not-advertise` command which is included in the correct answer, implying it's part of the required configuration.