How long after the sinking of the lusitania did the us declare war on germany?

On January 31, 1917, Germany, determined to win its war of attrition against the Allies, announced it would resume unrestricted warfare in war-zone waters. Three days later, the United States broke diplomatic relations with Germany, and just hours after that the American ship Housatonic was sunk by a German U-boat.

b. the american revolution

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."