As of January $1,20$X$8,$ Willard Company decided to change from the LIFO method of inventory valuation to the FIFO method. For this problem, ignore income taxes. Data for the past four years $($including $20$X$8)$ are as follows:

$20$X$820$X$720$X$620$X$5$

Cost of goods sold$$LIFO $1,200900720600$

Ending inventory$$LIFO $200150120100$

Ending retained earnings$$LIFO $1,6681,188828540$

Cost of goods sold$$FIFO $1,170880710595$

Ending inventory$$FIFO $300220170140$

In this problem, Willard Company has no expenses except for cost of goods sold. In its $20$X$8$ financial statements, Willard will restate its $20$X$7$ and $20$X$6$ financial statements and report the Cost of Goods Sold$$FIFO and Ending Inventory$$FIFO numbers. Willard will also need to report an adjusted Retained Earnings balance as of the beginning of $20$X$6.$ The originally reported Retained Earnings balance on that date, using LIFO, was $$540($the $20$X$5$ ending balance$).$

What is the retrospectively recalculated Retained Earnings balance as of January $1,20$X$6,$ after the change to FIFO is made?

Note: Ignore income taxes.

$$580$

$$640$

$$680$

$$400$