The correct answer is option 4: <em>"Are you saying that in 10 years the city's tax income will be 70 percent less than this year?"</em>
In this option, the meaning of the statement is preserved. The amount of years that will take for the change to be made is the same: <u>ten years</u>. The percentage of the shrink in the city's tax income, which is <u>70%</u>, is the same as in the statement; also, the idea of the <u>gradual change from this point in time until those ten years have passed</u> is also preserved. Thus the meaning of the whole statement is not distorted as in the other options.