单选题：根据下列材料，请回答题：It was sunrise on an August morning when the cap

根据下列材料，请回答题：
It was sunrise on an August morning when the captain and his crew cast their nets some 50 miles south of Louisiana in the Gulf of Mexico. As the net was pulled over, the contents were poured out followed by excited cries of "Coins! Coins!
" The fishermen quickly realized they had realized a fishermen's dream: sunken treasure! And not just any treasure, but early American silver dollars that had gone down 210 years earlier.
In 1784, at the end of the American Revolutionary War, a heavily armed ship was bund for the port of New Orleans. On board was a fortune in Spanish Silver Dollars. Hundreds of thousands of them were loaded for the trip to New Orleans, yet not a single one arrived. With no survivors from the ill-fated voyage, historians can only guess at what happened. Some say powerful storms took her down while others speculate it was treasure-hungry pirates (海盗) . Whatever happened, the secret -- along with a treasure valued near $100,000,000 in today's dollars -- was sent to a watery grave some 300 feet below the ocean's surface.
Spanish Silver Dollars were the favorite coins of colonial Americans. Widely used and accepted as payment in the thirteen colonies, the United States government gave them the status of official legal tender. Unfortunately, even though they were struck in large quantities, not many of them survive today. After the Civil War, the government withdrew them from circulation and they were melted down.
Due to the historic discovery of the treasure, GovMint.com is releasing these coins to the public for an amazingly low price. For a limited time, these authentic silver dollars are priced at$49 plus shipping and handling -- a dramatic reduction from the market price of this coin anywhere else worldwide.
What surprised the fishermen on an August morning?
A. Their net contained a big strange-looking fish.
B. They found the treasure sunken 210 years ago.
C. They found some pieces of a sunken ship in the net.
D. Their net suddenly got caught by something deep in the water.