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) nuclear energy d) coal

B - Petroleum

Wood was one of the first energy sources, way before the nineteenth century so you can rule that choice out.

Nuclear Energy is more advanced and closer to the twentieth century so you can also rule that out.

And coal was before petroleum, around mid to late eighteenth century possibly.

Hope this helps!