Which two pieces of information should you acquire before you troubleshoot an STP loop?
(Choose two.)

A.
topology of the routed network

B.
topology of the switched network

C.
location of the root bridge

D.
number of switches in the network

Explanation:
Forwarding loops vary greatly both in their origin (cause) and effect. Due to the wide variety of
issues that can affect STP, this document can only provide general guidelines about how to

troubleshoot forwarding loops.
Before you start to troubleshoot, you must obtain this information:
STP configuration details, such as which switch is the root and backup root, which links have a
non-default cost or priority, and the location of blocking ports
Reference: http://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-treeprotocol/28943-170.html