D seems to be the most correct. Hope that helps!
In February 1915, Germany announced unrestricted warfare against all ships, neutral or otherwise, that entered the war zone around Britain. One month later, Germany announced that a German cruiser had sunk the William P. Frye, a private American vessel that was transporting grain to England when it disappeared.
Answer:
Image result for Pirate raiding of American merchant ships lead to these wars?
The cause of the U.S. participation was pirates from the Barbary States seizing American merchant ships and holding the crews for ransom, demanding the U.S. pay tribute to the Barbary rulers. United States President Thomas Jefferson refused to pay this tribute. Sweden had been at war with the Tripolitans since 1800.
Explanation:
brainlyest plz if u would be so kind :)