Final answer:
The author's purpose to entertain is best shown through whimsical language and playful dialogue, indicating a humorous story meant to delight children.
Step-by-step explanation:
The part of the excerpt that best demonstrates that the author's purpose is to entertain children with a humorous story is b) the use of whimsical language and playful dialogue. When an author uses whimsical language and playful dialogue, it often signifies an intention to delight the audience through humor and light-heartedness. This is in contrast to detailed descriptions of anatomy, historical backgrounds, or serious tones, which are more likely to serve informational or educational purposes.
In analyzing the author's purpose, it's useful to look at aspects such as figurative language, the role of trickster characters, and the use of sensory detail. These elements can contribute to making the story immersive and entertaining. For example, the use of vivid descriptions and imaginative metaphors adds to the humor by portraying situations or characters in a fun and exaggerated manner, which is especially engaging for children.