The income statements of TAN Company for June and July of the last year are as follows:
	June	July
Sales	600	680
Cost of goods sold	420	460
Gross margin	190	190
Selling and administrative expenses	185	195
Income before tax	5	-5

Using High-low method, the variable component of cost of goods sold is

	a.	0.50
	b.	0.25
	c.	1.25
	d.	0