A signed agreement is a signature on a piece of paper and is a powerful legal piece between two parties.
I'm very sure that the answer to your question is D: To leave a lasting mark.
Sorry if this is wrong, have a good day!
a. Air raid on Pearl Harbor
b. nothing
c. September 1, 1939 - Germany invades Poland
d. Germany and the Soviet Union sign a non-aggression pact
I'm guessing its a and c
I think aproximently about 1990