Final answer:
Argentina adopted a currency board to fix its peso to the USD mainly to control rampant inflation by providing a stable exchange rate and enforcing fiscal discipline to prevent the excessive issuance of money.
Step-by-step explanation:
The main motivation for Argentina adopting a currency board and fixing the peso to the USD in the early 90s was to tame inflation. By pegging the Argentine peso to the US dollar at a one-to-one rate, Argentina aimed to stabilize its currency and overall economy. This move was seen as a mechanism to reduce the hyperinflation that had plagued the country, by providing a stable exchange rate, which would help in regaining public confidence in the national currency and encourage foreign investment.
Moreover, a currency board enforces a fiscal discipline, as it requires the central bank to hold reserves in the anchor currency. This prevents the central bank from printing money recklessly, which is a common cause of high inflation. While fixing the exchange rate can have other effects, such as potentially creating an overvalued real exchange rate, the primary aim for Argentina was inflation control, not boosting export competitiveness or joining the United States as a territory.