Which Margin Formula Do Banks Generally Apply to Loans on the Basis

Which margin formula do banks generally apply to loans on the basis of a line of credit?

A) 10 percent of the value of accounts receivable plus 60 percent of inventory
B) 50 to 80 percent of the value of accounts receivable plus 50 percent of inventory
C) 20 percent of the value of accountants receivable plus 20 percent of inventory
D) 30 percent of the value of accounts receivable plus 15 percent of inventory