You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.
--------
Question: Question: A shirt goes on sale for 80% of its original price. One week later, the sale price is marked down 20%. The final price is what percent of the original price?

 Option A: 72%

 Option B: 70%

 Option C: 52%

 Option D: 64%

 Option E: 28%

Answer: Option D


Question: Question: The purchase price of an article is $48. In order to include 5% of cost for overhead and to provide $12 of net profit, the markup should be

 Option A: 15%

 Option B: 25%

 Option C: 30%

 Option D: 40%

 Option E: 45%

Answer: Option C


Question: Question: Find the area between two concentric circles defined by
x2 + y2 -2x + 4y + 1 = 0
x2 + y2 -2x + 4y - 11 = 0

 Option A: 11 Pi

 Option B: 12 Pi

 Option C: 13 Pi

 Option D: 14 Pi

 Option E: 15 Pi

Answer:
Option B