Given the following Ending Inventory errors for the Portland Company: Year 2016 2017 Ending Inventory Error Understated $30 Understated $20 Indicate the error in 2017 Net Income and 12/31/17 Retained Earnings: Select one: O a. Net Income Understated $20, Retained Earnings Overstated $20 O b. Net Income Overstated $50, Retained Earnings Overstated $20 Oc Net Income Overstated $10, Retained Earnings Understated $20 O d. Net Income Understated $50, Retained Earnings Understated $20 Oe. Net Income Understated $10, Retained Earnings Understated $10