The writer should add this sentence after sentence 15 for the following reason: Yes, because it provides a personal example that illustrates Rowe's claims in the paragraph.
Why the sentence should be added
Adding the sentence about the plumber's experience strengthens the paragraph by providing a concrete example to support Rowe's claim that people can find fulfillment in unexpected ways, demonstrating that passions can develop over time, even in seemingly unrelated fields and making the argument more relatable and engaging for the audience.
The other options are not directly supported by the sentence because while the example mentions the plumber's decision-making process, it does not provide a generalizable set of steps for all students.