The "Red-Line Method" Refers To

The "red-line method" refers to:

A) the policy of drawing a red line around certain neighborhoods on a map and then refusing to sell on credit to people who live within those areas.
B) restrictions imposed on companies which use a just-in-time inventory system.
C) a red line that shows the maximum amount of credit that should be extended to a customer.
D) a method of controlling inventories by drawing a red line around the inside of a bin.
E) a method of controlling receivables by drawing a red line on invoices of companies that are expected to pay late.