A single-elimination (knockout) draw is really a bracket with a fixed number of "slots," and that number of slots always has to be a power of 2, because each round exactly halves the field. To fit 17 teams into such a bracket, we need to find the bracket size and see how many empty slots (byes) are left over.
Since a knockout bracket can only be built at sizes that are powers of 2, and 32 is the smallest such size that can hold 17 teams, the leftover, unfilled slots, and therefore the byes, must number 15.
Therefore, the correct answer is 15.
