105. Read the following passage, then answer the question below.

Few financial stories are retold as often as tulip mania. According to the popular version, in the 1630s the people of the Dutch Republic became so obsessed with tulips that a single bulb could cost more than a house, and when prices collapsed in early 1637, thousands were ruined. The tale was fixed in the public imagination by Charles Mackay, a Scottish journalist whose 1841 book on mass delusions described the episode in vivid detail and has been cited ever since as a warning about speculative bubbles.

Recent historians have been far more cautious. The tulips that commanded the highest prices were rare varieties whose petals were streaked with flame-like patterns. Growers did not know that the streaks were caused by a virus, which also weakened the bulb, so the prized varieties were hard to multiply, and their scarcity was genuine. Moreover, in the winter months, when bulbs were still in the ground, traders bought and sold written contracts promising delivery in spring. These contracts allowed people with little capital to bet on future prices, and many were passed from buyer to buyer without any bulb changing hands. When the market faltered in February 1637, some buyers simply refused to honor their contracts.

Yet the evidence for widespread ruin is thin. The historian Anne Goldgar searched Dutch archives for the bankrupt tulip investors that the legend promised and found remarkably few. Courts negotiated settlements, and the larger economy of the Netherlands continued to flourish. This does not mean that nothing unusual happened; prices did climb and fall with astonishing speed. But the lesson of the episode may be less about collective madness than about how new financial instruments can let people gamble on assets they never intend to own.

According to paragraph 2, all of the following helped make rare tulips costly EXCEPT