Final answer:
The Australian Army unit responsible for domestic counterterrorism is the Special Operations Command, which includes Tactical Assault Groups dedicated to counterterrorism tasks.
Step-by-step explanation:
The unit within the Australian Army that has the remit for domestic counterterrorism is the Special Operations Command (SOCOMD). SOCOMD incorporates various units, including the Tactical Assault Groups (TAG), which are specifically trained and equipped to undertake counterterrorism duties in Australia. TAG-East and TAG-West are the two main Tactical Assault Groups responsible for covering different geographical areas within Australia. The options listed, such as the Intelligence Corps, play supportive roles but are not primarily tasked with counterterrorism.