Final answer:
Option B is the best summary of 'A Busy, Happy Summer,' as it captures the text's emphasis on the enjoyment and activity during the summer.
Step-by-step explanation:
The best summary of the text titled "A Busy, Happy Summer" appears to be option B. The text highlights the joy and activity of a lively summer. This choice is most aligned with the textual evidence provided, which consistently describes instances where the summer's events are engaging and pleasant. For example, transitions in the text, such as "Well, one matchless summer's day..." indicate a flow of time filled with positive experiences. Furthermore, the text maintains a focus on a central narrative which is organized around a series of events that form a coherent and lively description of summer activities.