The answer is negative 1. This is because the sequence follows a pattern of the final number being 4, then 9, then 4 again. near the end of the sequence, you will end at the term of positive 4, which when 5 is subtracted from it (the pattern is -5), the first negative term is -1.
To find the answer you need to fin the discount. So basically I did 16x15 and got 240. Than I divided that by 100. I got 2.40.Than I subtract 2.40 from 16 and got $13.60. Therefore it would be B