Answer:
B. looking into Miss Lottie's eyes and
seeing her in a new way.
Explanation:
What actually led to Lizabeth's revelation about what she had done is at the point she looked into Miss Lottie's eyes and saw her in a new way.
Below is an excerpt that supports that:
“For as I gazed at the immobile face with the sad, weary eyes, I gazed upon a kind of reality which is hidden to childhood. The witch was no longer a witch but only a broken old woman who had dared to create beauty in the midst of ugliness and sterility. She had been born in squalor and lived in it all her life. Now at the end of that life she had nothing except a falling- down hut, a wrecked body, and John Burke, the mindless son of her passion. Whatever verve there was left in her, whatever was of love and beauty and joy that had not been squeezed out by life, had been there in the marigolds she had so tenderly cared for."
When Lizabeth looked at the face of Miss Lottie, she saw her in a different and new way. She was no longer the witch Lizabeth knew her to be. Her eyes was filled with compassion as she saw a broken woman who stood before her. She saw Miss Lottie as an old woman whose precious possession, the marigolds have been destroyed and she was left with nothing.
At this point, Lizabeth understood the cruelty of what she has done. She discovered that the marigolds were Miss Lottie's only source of solace and beauty in a world that was ruthless and difficult.