For an S-Corp filling out an 1120S, how do I find the amount of interest deductions entered on line 13?

On my Income Statement I have Interest Expense of $7,500.00, Interest Income of $5,000.00, and Tax Exempt Interest Income of $2,500.00.

Also, my proffessor has marked my entry for Schedule K, line 16a Tax-exempt interest income as incorrect. I originally entered $2,500.00.