正解:B
In the output of R1, we see R1 has a default route to the Internet via G1/0, which is correct but R2 does not have this route. One reasonable answer of this issue is R1 has been configured as a stub router so it only advertised connected and summary routes. In Branch router output, we also see routes that are directly connected to R1 only.
Note: In this topology, only Branch router should be configured as stub, not R1 router.