Answer:
Option (3) is correct.
Explanation:
Given that,
Income elasticity of demand of watches = 0.7
Median income in the United States rises by 10%
Income elasticity = Percentage change in quantity demanded ÷ Percentage change in income
0.7 = Percentage change in demand for watches ÷ 10
Percentage change in demand for watches = 7%
Therefore, the demand for watches increase by 7%.