In Teaching the Patient How to Take His Own Blood

In teaching the patient how to take his own blood pressure,which of the following is true?

A) Blood pressure cuffs that are too small will give a falsely low reading.
B) Blood pressure cuffs that are too large will give a falsely high reading.
C) Electronic blood pressure cuffs are just as accurate as other methods.
D) The cuff should be placed directly over the skin and not over clothing.