During 2016, White company determined that machinery previously depreciated over 7-year life had a total estimated useful life of only 5 years. An Accounting change was made in 2016 to reflect the change in eestimate. If the change had been made in 2015, accumulated depreciation at December 31, 2015 would have been $1,600,000 instead of $1,200,000. As a result of this change, the 2016 depreciation expense was $100,000 greater than it would have been if no change were made. The income tax rate was 30% in both years. What is the proper amount of the adjustment to White's January 1, 2016 balance of retained earnings?

a. $280,000

b. $0

c. $100,000

d. $400,000