Final answer:
The provided excerpts do not contain the information needed to answer what the Headmaster of Yancy Academy sent to Percy's mom in Chapter 2, as it pertains to 'The Lightning Thief' and is not referenced in the provided texts.
Step-by-step explanation:
The question asks what the Headmaster of Yancy Academy sent to Percy's mom in Chapter 2. However, none of the provided excerpts supply the information needed to directly answer that question.
To respond to the student, we'd need a specific reference from 'The Lightning Thief' by Rick Riordan, as that is the book where Percy Jackson is a character at Yancy Academy.
Since the necessary details are not present within the provided texts, we cannot answer the question about what the Headmaster of Yancy Academy sent to Percy's mom in Chapter 2.
This situation illustrates the importance of having direct references to the text in question when dealing with literature-related inquiries.