Which financial legislation required acceptance of paper money for all obligations during the Civil War?

The Legal Tender Act, passed in 1862, was crucial for financing the Union's efforts during the Civil War. This legislation declared that any paper currency issued by the U.S. Treasury was to be accepted as legal tender for all debts, public and private. This meant that creditors could not refuse paper money if offered as payment, effectively ensuring the circulation of greenbacks (the paper currency created by the act) and enabling the government to raise funds quickly to support the war effort.

The acceptance of paper currency helped to stabilize the economy during a time of great financial strain and uncertainty. By requiring acceptance of this paper money, the government could avoid relying solely on gold and silver reserves, which were limited and could not support the extensive borrowing and spending necessary for wartime financing.

Other options such as the Gold Reserve Act and the Currency Stability Act are not directly linked to the Civil War's financial strategies and responses at that time. The Greenback Currency Law, while related, is not the name commonly associated with the pivotal legislation of the era. Thus, the Legal Tender Act stands out as the correct answer.