请问一道CXD数学

If the value of a piece of property decreases by 10 percent while the tax rate on the property increases by 10 percent, what is the effect on the taxes? (D)

A) Taxes increases by 10%

B) Taxes increases by 1%

C) These is no change in taxes 

D) Taxes decreases by 1%

E) ) Taxes decreases by 10%

选D：设原来的property为P，tax rate为R，

根据题意：现在的税收为(1-0.1)P×(1+0.1)R=0.99PR

税率的变化=（现在-原来)÷原来=(0.99PR-PR)÷PR=-0.01,既降低1%