What was an unintended effect of the sinking of the lusitania?

a) nations turned against germany because of german tactics that caused the deaths of innocent travelers.
b) the allies realized unrestricted bombing would turn nations against them, so they developed new strategies.
c) both germany and the allies became suspicious of passenger ships, which often carried war supplies.
d) the united states sent diplomats to europe to negotiate an end to the fighting before more lives were lost.