Cisco ipx encapsulation arpa = Novell "Ethernet_II"
Cisco ipx encapsulation novell-ether = Novell "Ethernet_802.3"
Cisco ipx encapsulation sap = Novell "Ethernet_802.2"
Cisco ipx encapsulation snap = Novell "Ethernet_snap"
So, unless the "ethernet_11" in a. is a typo (should be ethernet_ii), then d. is the only correct match.