Which of the following ,if true, is the most logical completion of the argument below?

The tax system of the Republic of Grootland encourages borrowing by granting its taxpayers tax relief for interest paid on loans. The system also discourages saving by taxing any interest earned on savings. Nevertheless, it is clear that Grootland's tax system does not consistently favor borrowing over saving,for if it did, there would be no___.

A. tax relif in Grootland for those portions of a taxpayer's income, if any, that are set aside to increase that taxpayer's total savings

B.tax relief in Grootland for the processing fees that taxpayers pay to lending institutions when obtaining certain kinds of loans

C.tax relief in Grootland for interest that taxpayers are charged on the unpaid balance in credit card accounts

D.taxes due in Grootland on the cash value of gifts received by taxpayers from banks trying to encourage people to open savings accounts

E.taxes due in Grootland on the amount that a taxpayer has invested in interest-bearing savings accounts.

这道题的题目不是说这样的税收系统是不可能长久的偏好借贷，所以，如果这种税收系统实行，它会发生以下的某种情况吗？为什么答案回选a呢？a不就是解释这个税收系统如何免税吗？请大家帮忙看看好吗？