Answer: C "’Let me think about this,’ she said. ’Can I be by myself for a while?’"
Step-by-step explanation:
The quote from the passage that best illustrates the theme of trusting oneself is "’Let me think about this,’ she said. ’Can I be by myself for a while?’"
The above statement shows that Martha wanted to have a deep rethink about the situation at hand and then know the decision to take.
Therefore, the correct option is C.