What is the difference between PBX and CENTREX?

		a. PBX is a custom switch provided by the PSTN, whereas CENTREX only provides certain standard features
		b. Organizational PBXs cannot be networked together, whereas CENTRX system can be networked together
		c. Both PBX and CENTREX switches are owned and operated by the organization using them vice the PSTN
		d. The PBX is a private organizational switch not owned or maintained by the PSTN, whereas CENTREX is a similar service owned and operated by the PSTN ACDs are non-blocking PBX switches that are typically used by organizations such as call centers. True False