Ah, I think you might not have taken REG yet, but basically, at end of every quarter (4 month or so) you have to make a estimated tax payment based on (a bunch of stuff covered in REG am too tired to explain)

Estimated Tax payments = Tax expense, really.

So imagine this, you are ABC corp. You estimate your sales to be X dollars this year, which translate to the $90,000 based on tax rate. You pay the government 90K.  

These payments are expensed, then at the end of the year you "settle" with the fed by filing a tax report. If your actual tax was less, then you get money back, if you "lowballed" your estimate, then you have to pay more. In this case, you clearly underestimated and now expect more expense.

In this question, they were really blowing smoke into your ear. The question did not ask for a DTA or liability-It just asked what the expense was- Which is Taxable Income X 30% =195K