Measuring blood pressure by feeling a radial pulse during cuff deflation is known as BP by:

Measuring blood pressure by feeling a radial pulse during cuff deflation is referred to as palpation. This method involves placing your fingers on the radial artery while slowly releasing the pressure from the cuff. As the cuff deflates, you monitor the point at which you can first feel the pulse again, which indicates the systolic blood pressure. This technique is particularly useful in situations where a stethoscope is not available or when the sounds associated with blood pressure measurement cannot be heard clearly.

Auscultation, on the other hand, is the traditional method of measuring blood pressure by using a stethoscope to listen for Korotkoff sounds while the cuff is being deflated. Inspection refers to visually examining the patient for any signs of medical conditions, and vibration does not pertain to blood pressure assessment techniques in this context. Thus, palpation is the correct choice here as it specifically relates to the method used to measure blood pressure by feeling a pulse.