I can't find that much information on it, I'm looking for something along the lines of preventing communism, easy question, I just can't find the answer.
sorry i wrote down the wrong president, i was thinking Truman, but I wrote down Hoover and didn't notice, i still have the same question though about Truman

as you Know berlin was inside East Germany or the DDR

and the west was trying to rebuild europe and the Gererman Mark was introduced

The introduction of the new currency was intended to protect western Germany from a second wave of hyperinflation and to stop the rampant barter and black market trade (where American cigarettes acted as currency). Although the new currency was initially only distributed in the three western occupation zones outside Berlin, the move angered the Soviet authorities, who regarded it as a threat. The Soviets promptly cut off all road, rail and canal links between the three western zones and West Berlin, starting the Berlin Blockade. In response, the U.S. and Britain launched an airlift of food and coal and distributed the new currency in West Berlin as well.

in the British sector the British used BAF'S as the courency British armed Forces over the Rhine

it was all Notes I have a 3 penny Note