A company provided data concerning the costs incurred to mow residential lawns for which customers pay $45 per mowing. Data for the past 7 months are as follows:

	January	February	March	April	May	June	July
Number of lawns mowed	200	110	150	100	220	120	210
Mowing cost	$12,900	$8,120	$10,200	$8,200	$13,060	$8,400	$13,280

How much are the estimated monthly fixed costs using the high-low method?

A) $8200

B) $2,444

C) $4510

D) $4150

D) $3,180