Final answer:
In 1906, the proposed selling price for the Wright brothers' airplane design in Europe was $200,000.
Step-by-step explanation:
The Wright brothers went to Europe in 1906 with the intention of selling their revolutionary airplane design. From the given options, the proposed selling price for their airplane design was c) $200,000. This price may seem low in today's terms given the historical importance and influence of their invention, but it was a sizeable amount for the time.
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