When Checking for Proper Blood Pressure Cuff Size, Which Guideline

When checking for proper blood pressure cuff size, which guideline is correct?

A) The standard cuff size is appropriate for all sizes.
B) The length of the rubber bladder should equal 80% of the arm circumference.
C) The width of the rubber bladder should equal 80% of the arm circumference.
D) The width of the rubber bladder should equal 40% of the arm circumference.