The inventory data for an item for November are:

Nov. 1	Inventory	20 units at $20
4	Sold	10 units
10	Purchased	30 units at $21
17	Sold	20 units
30	Purchased	10 units at $22

Using the perpetual system, costing by the first-in, first-out method (FIFO), what is the cost of the merchandise inventory of 30 units on November 30?

$620

$640

$610

$630