Answer:
they were no longer focused on issues involving illness and war
The British abandoned Boston in early 1776 because they were forced out of the country by the American soldiers.
American Revolutionary War was at large, and the Patriots, led by general Washington (who later became the first president of USA) won the battle at Boston, which was bloodless, by the way. This brought an end to an eight-year British occupation of the city.
B is the correct answer.
While the Indus Valley has gotten more attention in recent years, it is not considered one of the three classical civilizations.
