What statement is true?

A.
All nodes in a Multiple Peer Group PNNI Network have the same topology database.

B.
In a Single Peer Group PNNI Network, only the Peer Group Leader has a copy of the topology database.

C.
PNNI always calculates an optimal route.

D.
None of the above

Explanation:
The PNNI protocol communicates the state of a PNNI network in PNNI Topology State Elements (PTSEs). PTSEs are discrete messages that contain information about one of the following types of network components:
PNNI nodes
Reachable addresses
PNNI links between nodes
To enable communications with other nodes, each switch needs to have all the PTSE information for each switch in the network. Each node is responsible for flooding out its own PTSE information to all the other switches in the network.
Since up-to-date PTSE information is required for optimal routing decisions to be made, there are several different mechanisms in place to help ensure that all nodes have reasonably accurate PTSE information.