Final answer:
Before entering World War I, most Americans understood that the conflict would likely cost American lives, which reflects their aversion to joining what they viewed as a brutal and enduring war.
Step-by-step explanation:
Understanding American Sentiment Before WWI
Before the United States entered World War I, most Americans and leaders were against involvement in the conflict. They acknowledged President Wilson's policy of neutrality as one of the most popular stances in his first term, and they were generally relieved to be separated from Europe's tribulations. The American population was well aware of the horrors of trench warfare, thanks to uncensored news, and had no appetite to join the slaughter. Although the economy could potentially benefit from wartime production, the steeper price of American lives and the moral ambiguity of joining either side outweighed these considerations. Moreover, the American volunteer army was rather small, and its entry into the war at that time seemed unlikely to have a significant impact. A diverse population including Irish immigrants, who were anti-British, and German-American communities might have harbored mixed feelings about aligning with the Allies, which could have led to internal conflict.
Therefore, the most accurate understanding among Americans before their country entered World War I is that they recognized the war would likely cost American lives, which is option b. They knew the war was atrocious and long-lasting, and there was widespread reluctance to send troops overseas.