A.IR B.DSSS C.FHSS D.DSSS and FHSS E.IR, FHSS, and DSSS
A.802.1Q native VLAN frames are untagged by default. B.802.1Q trunking ports can also be secure ports. C.802.1Q trunks can use 10 Mb/s Ethernet interfaces. D.802.1Q trunks require full-duplex, point-to-point connectivity. E.802.1Q trunks should have native VLANs that are the same at both ends.
A.172.31.17.4/30 B.172.31.51.16/30 C.172.31.64.0/18 D.172.31.80.0/22 E.172.31.92.0/22 F.172.31.192.0/18