During the year ended 30 June 2015 Barry Ltd, pays quarterly tax installments as follows: $4000 on 28 October 2014, $11 000 on 28 February 2015, $12 000 on 28 April 2015. On 30 June 2015, Barry Ltd determines its total current tax liability for the year to be $33 000. The final tax installment for the year will be:
a. a refund of $2000
b. a payment of $33,000
c. a payment of $12,000
d. a payment of $6000