A stub network is defined as a network segment that is accessible by only one path (single entry/exit point). It does not serve as a transit network for routing between other networks. Traffic entering or leaving the stub network must pass through a single interface.
MTCNA Course Material - Routing Concepts:
"A stub network is one that is connected to the rest of the network by a single router interface. It has only one entry and one exit point." Rene Meneses MTCNA Study Guide - Routing Terms:
"Stub networks do not forward packets for other networks. They are endpoints with one route in and out." Other options:
* A/B: Describe transit networks, not stub
* C: Misleading-stub has both entry and exit, but only through one path
* D:#Correct definition