We intend to begin on the first of february unrestricted submarine warfare. we shall endeavor in spite of this to keep the united states of america neutral. in the event of this not succeeding, we make mexico a proposal of alliance on the following basis: make war together, make peace together, generous financial support and an understanding on our part that mexico is to reconquer the lost territory in texas, new mexico, and arizona. -zimmermann telegram, 1917

a. it led president wilson to issue a proclamation reinforcing u. s. neutrality.

b. it influenced president wilson to order attacks on german merchant ships.

c. it appealed to mexicans and caused mexico to join the war as a german ally.

d. it engaged americans and generated u. s. popular support for the declaration of war.