Answer:
B. wiring is complex
Step-by-step explanation:
The main disadvantage of a mesh topology is certainly that wiring is complex. It is used for military, home automation sorts of requirements. And each node is connected to the other node. So if one node fails, the network still works. Hence, the topology is a good one but the only pitfall is that it requires complex wiring and that is a disadvantage. And other options looks like an advantage rather than disadvantage.