Which of the Following Is True of the Markup Used

Which of the following is true of the markup used by different firms in the same line of business?

A) They are likely to use the same markup percentage,because they all want to have the same selling price.
B) They are likely to use the same markup percentage,because this is a government requirement.
C) They are likely to use the same markup percentage,because they are likely to have similar operating expenses.
D) They are likely to use the same markup percentage,because this is what is acceptable to manufacturers.
E) They are likely to use the same markup percentage only if they are in pure competition.