Final answer:
The main argument in favor of a stronger central government during the DC Heater debates was to preserve the Union and ensure the survival and efficient functioning of the new nation.
Step-by-step explanation:
The main argument in favor of a stronger central government during the DC Heater debates was A) To preserve the Union. Supporters of a strong central government argued that it was necessary for the survival and efficient functioning of the new nation. Without a stronger central government, the country would have been vulnerable to external threats, lacked the financial means to maintain defense and infrastructure, and would have struggled to repay its debts.