Final answer:
The type of Ethernet in the options provided is 1000BaseT, which represents Gigabit Ethernet over twisted pair cables.
Step-by-step explanation:
The type of Ethernet among the given options is (b) 1000BaseT. This terminology refers to a standard for Gigabit Ethernet over copper wiring. Ethernet is a technology for networking that allows devices to communicate over a metallic network of cables. The '1000' in 1000BaseT indicates the maximum data transfer rate of 1000 Mbps (1 Gbps), 'Base' refers to baseband signaling, and 'T' signifies twisted pair cables. Options such as (a) 4G and (c) 802.11ac are not types of Ethernet; instead, 4G is related to wireless mobile telecommunications technology, and 802.11ac is a wireless networking standard.