The Shopkeeper increased the price of a product by 25% so that customer finds it difficult to purchase the required amount. But somehow the customer managed to purchase only 64% of the required amount. What is the net difference in the expenditure on that product?  Choose the correct option:
A) 12.5%
B) 13%
C) 15%
D) 17%
E) 20%
Quantity X Rate = Price   1 x 1 = 1   0.64 x 1.25 = 0.8   Decrease in price = (0.2/1) × 100 = 20%   20%)
<result>E</result>
The Shopkeeper increased the price of a product by 25% so that customer finds it difficult to purchase the required amount. But somehow the customer managed to purchase only 64% of the required amount. What is the net difference in the expenditure on that product?