What was the most significant american contribution to the allied cause before 1942? ?

a. air support for allied troops
b. military ground force in the pacific
c. war materials leased to allied forces
d. atomic research of the manhattan project

lee and grant, both of whom held the highest rank in their respective armies, had known each other slightly during the mexican-american war (1846-48) and began their dialogue by exchanging awkward personal inquiries. characteristically, grant had arrived in his mud-splattered field uniform while lee had turned out in full dress attire, complete with sash and sword.

explanation: