Philadelphia Company has the following information for March:

Sales	$451,478
Variable cost of goods sold	222,774
Fixed manufacturing costs	75,330
Variable selling and administrative expenses	53,216
Fixed selling and administrating expenses	32,239

Determine the March:

a. Manufacturing margin	$fill in the blank 1
b. Contribution margin	$fill in the blank 2
c. Operating income for Philadelphia Company	$fill in the blank 3