Roland wants to buy a jacket that is discounted 20% off the regular price. Which of the following is NOT a valid way to determine the amount of the discount?

A
Move the decimal point of the original price one place to the left and then double it.

B
Set up a proportion with the ratio of the original price to the amount of the discount equal to the ratio 20 to 100.

C
Multiply the original price times 0.2.

D
Divide the original price by 5.