Let x represent amount of money that Tony needs to deposit to avoid a fee.
We have been given that Tony has $727.29 in his checking account. He wrote a check for $248.50 today.
Let us find amount of money left in Tony's account after writing a check of $248.50 as:

After depositing x dollars in account, total amount of money in Tony's account would be
.
Since Tony must maintain a $500 balance to avoid a fee, so amount of money is his account should be greater than or equal to 500.
We can represent this information in an inequality as:

Therefore, our required inequality would be
and option C is the correct choice.
Let us solve for x.



Therefore, Tony must deposit at-least $21.21 to avoid a fee.