The United States responded to the sinking of the Lusitania and other

passenger ships by

Aimmediately declaring war on Germany
Bforcing the creation of the Sussex Pledge
Centering a formal alliance with the Allied powers
Dissuing the Zimmerman Telegram
Edeclaring war on Mexico

Verified Answer :

C- entering a formal alliance with the Allied powers

b. Wilson called the action an act of barbarism but continued his push to keep the United States out of war.

In 1915, the passenger ship Lusitania was sunk by German submarines,
killing 128 Americans. Wilson demanded the end to the unrestricted use
of submarine warfare. Eventually, in March 1916, after the sinking of
the passenger ship Sussex, Germany issued the Sussex Pledge, stating
three important promises: (1) German submarines would no longer target
passenger ships; (2) merchant ships would not be attacked unless they
were known to be carrying weapons; and (3) provisions would be made for
personnel and passengers of merchant ships to get off the ship safely
prior to its destruction.