Respuesta :
A) In Philadelphia in the early 1800s, industries thrived because coal mines west of the city provided a huge fuel supply (I physically took the quiz and selected "a" and I got the question right.
A. In Philadelphia in the early 1800s, industries thrived because coal mines west of the city provided a huge fuel supply.
The original sentence does not show that the coal helped the industries thrive. The revision must show the connection between the two ideas: the city thriving and the huge fuel supply. Option B uses the conjunction but which indicates a contradiction. This does not work. Option C simply states that both ideas occurred in the 1800s. Option D uses the transition word although which is a concession. Neither idea is conceding to the other.