Answer: Purpose
Explanation:
The very Remarkable Helen Keller who had been born deaf and blind published the book 'Optimism' in 1903 after she had learned to speak, read, and write, with the help of her teacher Annie Sullivan.
She wrote the book and suggested Optimism to be a basic philosophy of life and believed that her Purpose had been to write that book to let people know that optimism even in the darkest of moments would get them through like she was able to.
The reason of Keller for writing "Optimism” is called her D. purpose.
Purpose in literature simply means the reason for doing a particular thing. In literature, the purpose depicts the idea of the author.
In this case, Keller wrote the book as a philosophy of life and believed that her purpose had been to write that book to let people know that optimism is important in life.
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