​A consumer values a house at $525,000 and a producer values the same house at $485,000.If the transaction is completed at $510,000,what level of tax rate will result in unconsummated transaction?

A) ​1%
B) 5%
C) 3%
D) ​2%

The transaction will only be unconsummated if the tax rate is greater than the difference between the consumer's and producer's valuation divided by the transaction price:
($525,000 - $485,000) / $510,000 = 0.098 or 9.8%.
Therefore, a tax rate of 5% would result in the transaction being unconsummated.