GMAT Reading Comprehension (RC) | Exactly when in the early modern era Native Americans began exchanging

(Line)Exactly when in the early modern era Native
Americans began exchanging animal furs with
Europeans for European-made goods is uncertain.
What is fairly certain, even though they left
(5)no written evidence of having done so, is that
the first Europeans to conduct such trade during
the modern period were fishing crews working the
waters around Newfoundland. Archaeologists had
noticed that sixteenth-century Native American
(10)sites were strewn with iron bolts and metal
pins. Only later, upon reading Nicolas Denys’s
1672 account of seventeenth-century European
settlements in North America, did archaeologists
realize that sixteenth-century European fishing
(15)crews had dismantled and exchanged parts of their
ships for furs.

By the time Europeans sailing the Atlantic coast
of North America first documented the fur trade, it
was apparently well underway. The first to record
(20)such trade—the captain of a Portuguese vessel
sailing from Newfoundland in 1501—observed that a
Native American aboard the ship wore Venetian silver
earrings. Another early chronicler noted in 1524 that
Native Americans living along the coast of what is now
(25)New England had become selective about European
trade goods: they accepted only knives, fishhooks,
and sharp metal. By the time Cartier sailed the Saint
Lawrence River ten years later, Native Americans had
traded with Europeans for more than thirty years,
(30)perhaps half a century.