Be sure you have read the page on the History of Encryption & Cryptography, before answering this question.

The history of the world has often turned on the ability or inability of a government or entity to decrypt a message or messages. The United States' entry into World War I was greatly affected by

Question $6$ options:

a$)$

the US breaking the JN$-25$ code

b$)$

the British breaking the German Zimmerman telegram

c$)$

the US breaking the Purple Code

d$)$

the breaking of the German Enigma machine