Final answer:
The fishermen possessed detailed knowledge of lake winds primarily (A) due to it being a traditional skill passed down through generations, enabling them to navigate and fish successfully.
Step-by-step explanation:
The fishermen likely have such detailed knowledge of the lake winds because it was a traditional skill passed down through generations. This knowledge historically comes from the necessity of understanding local weather patterns for fishing success, safety, and livelihood.
Traditionally, these skills are honed and transferred within communities over time, without external training programs or recent advancements in technology. Therefore, the correct answer is A) Because it was a traditional skill passed down through generations.