"soon after, the civil war began and thomas a. scott was tapped to supervise military transportation for the north. carnegie worked beside him. the war greatly boosted the iron industry. recognizing the opportunity, carnegie resigned from the pennsylvania railroad after the war in order to turn his attention to the iron industry. after hearing about the loss of an important wooden bridge on the pennsylvania railroad due to fire, carnegie organized a company to build iron bridges. this company, the firm of piper and schiffler, was later merged into the keystone bridge company in 1863." which statement below is the most accurate description of the cause-and-effect relationships in the passage? a. the civil war caused carnegie to become involved in the iron industry, which caused him to witness the boom in demand for iron; this in turn caused him to organize a company that built iron bridges. b. carnegie's resignation from the pennsylvania railroad company caused him to organize a company to build iron bridges, which in turn caused him to notice the great demand for iron caused by the civil war. c. the fact that thomas a. scott was supervising the military transportation for the north caused carnegie to notice a boom in the demand for iron; this in turn caused carnegie to organize a bridge-building company. d. the civil war caused carnegie to resign from the pennsylvania railroad company, which caused him to become involved in the iron industry; this in turn caused him to notice the great demand for iron caused by the civil war.