Answer: C) joyful.
Step-by-step explanation: the tone of a text is the author's or speaker's attitude towards the audience, the subject or even the characters of the text. There are many different kinds of tones, for example: happy, positive, sad, negative, objective, angry, etc. In the given excerpt from "The Wind in the Willows" by Kenneth Grahame the words with positive connotations (sparkles, bubble, free, playmates, laugh, chuckling, etc), give the excerpt a joyful tone.