Final answer:
Option b) best reflects the cultural viewpoint unique to Frithiof's culture, depicting the era's acceptance of the Vikings' piracy and actions as respectable.
Step-by-step explanation:
The best quotation that reflects a viewpoint unique to Frithiof's culture is option b): "For many years he lived the life of a pirate or viking, exacting tribute from other ships or sacking them if they would not pay tribute; for this occupation in the days of Frithiof was considered wholly respectable." This quote succinctly illustrates the cultural perspective regarding the lifestyle and activities of Vikings during the time of Frithiof. The mention of piracy and tributes being seen as respectable showcases the difference in societal norms and moral parameters compared to modern-day perspectives. The quotation indicates a time when Vikings like Frithiof engaged in activities like piracy which were not only common but also regarded as honorable within their society.