he following information is available for a company's cost of sales over the last five months.

Month	Units sold	Cost of sales
January	400	$31,000
February	800	$37,000
March	1,600	$49,000
April	2,400	$61,000

Using the high-low method, the estimated total fixed cost is:

$25,000

$30,000

$13,692

$100,000

$50,000

*please provide full calculation