SUSSEX Pledge a. increased the size of the army and the National Guard
b. suggested an alliance between Mexico and Germany
c. took over the railroads
d. set up a draft
e. planned cooperation among all countries
f. improved relations between Germany and the United States for
a time
g. prohibited interference with the war effort
h. helped to finance the war

f. Improved relations between Germany and the United States for  a time.

Explanation:

The Sussex Pledge was the agreement between the US and Germany over the issue of torpedoing a ship on suspicion of carrying any contraband or military supplies. This pledge allows a short respite between the two nations and also prevented the US from getting involved in the 1st World war.

The issue of unrestricted submarine warfare had been going on until the United States intervened after numerous deaths of American citizens in the ships attacked. To prevent the US from getting involved or participating in the war, Germany agreed to the Sussex Pledge after the attack on the passenger steamer, the Sussex. This pledge indicated Germany's promise to attack only ships carrying military arms, and also to attack only after giving the passengers and crews to vacate.  

This act allowed peaceful relations between the two nations and also successfully prevented American participation in the War, thus successfully aiding Germany in the war without the US joining the fight. This agreement provided some peace between the two until 1917 after which the warfare resumed and America entered the war on the side of the Allied Powers.

there are no mutiple choices here