This question, Unit 23 Quiz - #8, is a mistake in the manual. Please review the Taxation of Medical Expense Insurance on page 371.
Let's remember that the threshold for deduction is 10% of the AGI (Adjusted Gross Income). So, 10% of $29,000 is $2,900. To determine the amount that is deductible, we take the expenses, $3,000, and subtract $2,900 and the amount deductible is $100.