Respuesta :
I think it would be "She was careful now to be always clean and tidy." I'm not 100% sure, but this seems like the best answer.
The phrase from the passage that most directly indicates a recent influence on Heidi's life is "she was careful now to be always clean and tidy"
The key word is the word NOW this makes reference to a recent change on her behavior that it's related to a recent influence.
The other options don't give any elements that can help us to connect them to a recent change or event.