The correct answer is B. The narrative successfully establishes a clear focus because all the details relate to the family's first canoe trip.
Explanation
The focus of a text is the central theme that it deals with, for example, in the text of the question, the focus is a family's trip to a canoe adventure on the river since the author refers to this event repeatedly. He first mentions when the parents plan the plan; second, the author refers to the fact that no member of his family has carried out this activity before; thirdly, he refers to the preparations to go to the river; finally, it refers to the excitement the family had just before starting their canoe adventure. Therefore, the correct answer is B. The narrative successfully establishes a clear focus because all the details relate to the family's first canoe trip.