Answer:
a
Explanation:The term Iron Curtain had been in occasional and varied use as a metaphor since the 19th century, but it came to prominence only after it was used by former British prime minister Winston Churchill in a speech at Fulton, Missouri, U.S., on March 5, 1946, when he said of the communist states,
I hope you pass
The US intelligence beforehand had deciphered messages laying out the Japanese plan.
Answer: The two answers are B and C, or the second one and third one.
1840s
Factory-made agricultural machinery increases farmers' need for cash and encourages commercial farming
1841
Practical grain drill patented
1842
First grain elevator, Buffalo, NY
1843
Sir John Lawes founded the commercial fertilizer industry by developing a process for making superphosphate
1844
Practical mowing machine patented
1847
Irrigation begun in Utah
1849
Mixed chemical fertilizers sold commercially
