Which of the following equations is correct??

A. Gross Profit Sales Direct expenses Purchases Closing stock = Opening stock
B. Gross Profit Sales Direct expenses Purchases- Closing stock = Opening Stock 
C. Gross Profit Opening Stock Direct expenses Purchases- Closing stock = Sales
 
D. Gross Profit – Opening Stock Direct expenses Purchases Closing stock = Sales

During the year 2011-2012, the value of closing inventory was overstated by 25,000. Which of the following is true??

A. The cost of goods sold was overstated during 2011-2012 and income will be understated during 2012-2013
B. The income was overstated during 2011-12 and closing inventory will be overstated during 2012-2013 
C. The retained earnings was overstated during 2011-2012 and retained earnings will be understated during 2012-2013
 
D. The cost of goods sold was understated during 2011-2012 but retained earnings will not be affected during 2012-2013