The nurse detects a possible extra heart sound while assessing an adult client. To verify this finding, which action should the nurse take?

Choice A reason: The diaphragm of the stethoscope is best for high-pitched sounds such as S1 and S2, but extra heart sounds like S3 and S4 are low-pitched and may be missed using only the diaphragm. Choice B reason: The bell of the stethoscope is specifically designed to detect low-pitched sounds, including extra heart sounds like S3 and S4, and murmurs. This makes it the most appropriate tool for verifying an extra heart sound. Choice C reason: Doppler ultrasound is used to assess blood flow and detect vascular abnormalities, not for auscultating heart sounds during a physical exam. Choice D reason: Pulse oximetry measures oxygen saturation and does not provide any information about heart sounds or cardiac auscultation.