John Deere and Cyrus McCormick invented machines that made large-scale agriculture possible, especially in the Midwest. What were those machines?

steel plow and reaper

Explanation:

John Deere was the inventor of steel plow, invented in 1837. His invention was a breakthrough for farmers and agriculture. The plow that farmers previously used was often interrupted by the sticky prairie soil that used to get stuck on the plows. But the steel plow, that John Deere invented, helped the farmers to plow the field without interruption or pausing to clean the plow.

Cyrus McCormick was the inventor of Mechanical reaper, invented in 1831. Mechanical reaper was used by the farmers to reap the harvest using machinery. Previously, the farmers used to harvest crops using a sickle. This mechanical reaper helped the farmers to reap the harvest quickly and in less time.

So, the correct answer is steel plow and mechanical reaper.

i think it's b or c hope this