Answer:
Garry has balanced his checkbook correctly.
Explanation:
To Balance the checkbook correctly one must have the same balance in his check register and bank statement .
So, the given options are :
Gary: the balance in his check register is $500 and the balance in his bank statement is $500.
Gail: the balance in her check register is $400 and the balance in her bank statement is $500.
Gavin: the balance in his check register is $500 and the balance in his bank statement is $510
Since we can see that in case of Gary there is the same balance in his check register and his bank statement .
So ,Garry has balanced his checkbook correctly.