In networking, what does the acronym STP refer to?

In networking, what does the acronym STP refer to?

• Secure Telephony Procedure
• Stacked Terminal Policy
• Standard Topology Practice
• Spanning Tree Protocol 

EXPLANATION

The Spanning Tree Protocol (STP) is a network protocol that builds a loop-free logical topology for Ethernet networks. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them.
Spanning-Tree Protocol (STP) is a link management protocol that provides path redundancy while preventing undesirable loops in the network. ... In a STP environment, the switches exchange information amongst themselves using bridge protocol data units (BPDU) and will then listen in on all ports for this BPDU message.