As steel replaced iron, people also began looking for new fuels. which of the following fuels became popular in the late nineteenth century?

a.
wood

b.
petroleum

c.
coal

d.
nuclear energy

Hey there 

As steel replaced iron, people also began looking for new fuels. The fuels that became popular in the late nineteenth century was petroleum.  If your question was about steel replacing iron then the answer is coal. Steel replaced iron before the late 19th century. 

First c, then b - good luck