In this excerpt, pivotal is referring to the year 1775. The passage is saying that the year 1775 marked a turning point that was critical in the development of the American colonies.
Before 1775, the only manifestation of the massive public discontent with the abusive British tax laws had been unarmed resistance. After 1775, this struggle became an armed one and transformed in the War for Independence that would make the American colonies an independent nation free from the British crown.
Using the context clue, the best definition of pivotal as it is used here is critically important. So, the right option is B.
<u>Explanation</u>:
John Buchanan’s “The Road to Valley Forge,” narrates the complete story of how Washington grew from an inexperienced BackwoodsGeneral to a true Commander-in-Chief of a fighting force. America's greatest hero is revealed through the book.
He was intelligent and courageous who struggled desperately to learn from his mistakes, who converted a diverse mix of militiamen into a real army, and who exhibited to all the Americans that they could become create their own destiny. So, 1775 was a pivotalyear for the Americans because that year was a turnaround point in their lives.