Final answer:
Changes in production methods, reducing the need for farm labor, made the largest contribution to the occurrence of the Industrial Revolution.
Step-by-step explanation:
The factor that most likely made the largest contribution to the occurrence of the Industrial Revolution was changes in production methods, reducing the need for farm labor. The shift from manual labor to machines, driven by new inventions and technologies, enabled the mass production of goods and created a need for workers in factories. This led to rapid urban migration and a shift in the population from rural areas to urban centers.