Which of the Following Statements Describes a Control Weakness

Which of the following statements describes a control weakness?

A) Purchasing procedures are well designed and are followed even when the purchasing supervisor wishes to direct otherwise.
B) Pre-numbered blank purchase orders are secured within the purchasing department.
C) Normal operational purchases fall in the range from $500 to $1, 000, with a single signature required for purchases over $1, 000.
D) The purchasing agent in a personal capacity invests in a publicly-traded mutual fund that lists the stock of one of the company's suppliers in its portfolio.