Answer:
The innovation that most strongly caused the emergence of a nationwide market for farm produce in England was the steam engine.
The steam engine powered the Industrial Revolution and transformed the way goods were produced, transported, and sold. With the introduction of steam-powered machinery and transportation, it became possible to produce goods on a much larger scale and transport them much more efficiently and quickly than before. This allowed for the creation of a nationwide market for farm produce, as goods could be transported across great distances without spoiling.
While innovations such as the seed drill and the cotton gin played important roles in improving agricultural productivity, they did not have as significant an impact on the emergence of a nationwide market for farm produce as the steam engine did. The Bessemer process, which was used to mass-produce steel, was an important innovation in the later stages of the Industrial Revolution, but it did not have a direct impact on the development of a nationwide market for farm produce.