Select the correct statement(s) regarding DCE and DTE interfaces. a. the DCE and DTE convention describes devices and not interfaces b. to establish data flow, DTE interfaces must always be connected to other DTE interfaces, and DCE interfaces must always be connected to other DCE interfaces c. DCE and DTE device descriptions are unique to IEEE 802.3 Ethernet LANs d. the DCE and DTE convention describes the interfaces associated with devices; a single device may have both a DTE and DCE interface to enable correct data flow