Garza Corporation has two production departments, Casting and Customizing. The company uses a job-order costing system and computes a predetermined overhead rate in each production department. The Casting Department's predetermined overhead rate is based on machine-hours and the Customizing Department's predetermined overhead rate is based on direct labor-hours. At the beginning of the current year, the company had made the following estimates:

	Casting		Customizing
Machine-hours		20,000		13,000
Direct labor-hours		1,000		7,000
Total fixed manufacturing overhead cost	$	152,000	$	68,600
Variable manufacturing overhead per machine-hour	$	2.10
Variable manufacturing overhead per direct labor-hour			$	4.30

The predetermined overhead rate for the Casting Department is closest to:

a	$7.60 per machine-hour
b	$27.71 per machine-hour
c	$9.70 per machine-hour
d	$2.10 per machine-hour