A Postoperative Surgical Patient Asks How the Sequential Pneumatic Compression

A postoperative surgical patient asks how the sequential pneumatic compression boots applied in the operating room will help lower the risk of blood clots forming in the legs. The nurse's most appropriate response would be that the boots:

A) measure pressure in the leg blood vessels and sound an alarm if pressure rises.
B) alternately compress and release to help blood flow through vessels.
C) provide gentle continuous compression at low pressure.
D) provide firm continuous compression at high pressure.