Which of the Following Would Be an Appropriate Improvement to Controls

Which of the following would be an appropriate improvement to controls over large quantities of consumable material that are charged to expense when placed in bins which are accessible to production workers?

A) Relocate bins to the inventory warehouse.
B) Require management to compare the cost of consumable items used to the budget.
C) Lock the bins during normal working hours.
D) None of the above actions are needed for items of minor cost and size.