A theater offers a 20% discount to senior citizens on all tickets. The regular cost of a matinee ticket is $9.75.
Which expression represents the cost of a matinee ticket after the discount is applied?
A. $9.75 * 1/5
B. $9.75 * 4/5
C. $9.75 * 6/5
D. $9.75 * 9/5
Thank you for helping me! Also, if you do answer could you explain how you got your answer, it would really help me understand it more. Thanks! <3