Answer:
The question is incomplete, but A. is correct.
Explanation:
Charles Darwin published the Origin of Species in 1859.
He said that the Origin of Species was a work that he had started 20 years earlier, but he did not finish it until 1859.
The reason why he rushed to its publication was a letter that he received from his friend Alfred Russel Wallace who wrote to Darwin that he too was close to figuring everything that Charles already knew...
