How was $2.80 calculated?

Bethany is selling lemonade, but she is wondering what to charge. There are 5 people willing to buy lemonade, Jake, Jill, John, Jimmy, and Jessica. Jake is only willing to spend 50, Jill will spend $1, John will spend $1.50, Jimmy will spend $2, and Jessica will spend $2.50. Each cup of lemonade costs Bethany 60. 8c. What is the maximum profit that Bethany can make? A. $0 B. $1.60 C. $2.70 D. $2.80 E. $9.50