Answer:
b) $20,000
Explanation:
Retained Earning ending balance of 2015 = Opening balance of 2015 + Profit for the year 2015 - Dividend Paid during 2015
$400,000 = $320,000 + $100,000 - Dividend Paid during 2015
$400,000 = $420,000 - Dividend Paid during 2015
Dividend Paid during 2015 = $420,000 - $400,000
Dividend Paid during 2015 = $20,000
The firm's dividend payment for 2015 is $20,000.