Step 1: Understanding the Question
The question asks for the name of the medical instrument used to measure blood pressure.
Step 2: Defining the Instruments
(A) Anemometer: An instrument used for measuring wind speed and direction.
(B) Tachometer: An instrument that measures the rotational speed of a shaft or disk, as in a motor or other machine. It usually displays revolutions per minute (RPM).
(C) Sphygmomanometer: This is the correct medical term for a blood pressure monitor or cuff. It consists of an inflatable cuff, a measuring unit (manometer), and a mechanism for inflation.
(D) Speedometer: An instrument on a vehicle's dashboard that indicates its speed.
Step 3: Final Answer
A sphygmomanometer is the instrument used to measure blood pressure. Therefore, option (C) is the correct answer.