Final answer:
The command 'default-information originate' is used to advertise the default route to all other routers in dynamic routing protocols like OSPF and EIGRP.
Step-by-step explanation:
The command used to advertise the default route to all other routers to avoid manual configuration is c. default-information originate. This command is used in conjunction with routing protocols like OSPF and EIGRP to inform other routers of the presence of a default route.
This is a more dynamic approach compared to manually setting up default routes on each router.