Area 1 should be an NSSA because of the ASBR advertising EIGRP routes.

In Intermediate System-to-Intermediate System (IS-IS) Protocol, there are two types of networks:
point-to-point and broadcast. Unlike Open Shortest Path First (OSPF) Protocol, IS-IS does not have other network types like non-broadcast and point-to-multipoint.

Answer C should be responsible for timer optimization.
Answer E should be the proper design in an "IS-IS Hybrid topology design".
(L1/L2 routers maintain a separate lin-state database for L1 routes and L2 routes > This increases their CPU > So Access routes should never be both L1/L2 devices, only pure L1 devices)

A totally stubby area does not flood network summary LSAs (Type 3). It stifles Type 4 LSAs, as well. Like regular stub areas, totally stubby areas do not flood Type 5 LSAs. A totally stubby area sends just a single LSA for the default route.