The correct option is C less by Rs.510
Cash receipt is to entered on the debit side of the cash column in the cash book and no entry of this would be shown in the pass book as the bank balance is not affected due to this transaction. But, here cash receipt of Rs.5100 was wrongly posted on the credit side of the bank column in the cash book as Rs.510. Any entry on the credit side of the bank column in the cash book indicates payment through bank balance, so the error occurred here would lead to the bank balance as per cash book being less by Rs.510 .