Final answer:
Based on the provided information, August's mom is a teacher at August's school.
Step-by-step explanation:
Based on the provided information, it can be inferred that August's mom is a teacher at August's school. The text mentions that she is one of the best students and has a broad and thorough training, which suggests that she is knowledgeable in her field and likely teaching in a school. Additionally, the statement, 'If I could afford a private teacher for my own children I know of no one whom I would sooner have,' indicates that she is involved in teaching.
Although the other options mentioned in the question, such as being a doctor or absent from August's life, are not supported by the provided information.
Keywords: August's mom, teacher, school