Which of the following is an instrument used to measure?

The suffix "-meter" is used in medical terminology to denote an instrument that measures a specific quantity or quality. For example, a thermometer measures temperature, a sphygmomanometer measures blood pressure, and a audiometer measures hearing ability. This suffix is essential in various scientific and medical contexts where quantitative assessment is necessary.

In contrast, the other suffixes serve different purposes: "-ary" refers to something relating to or connected with, "-ectomy" indicates a surgical removal of a part or tissue, and "-centesis" describes a procedure using a needle to puncture a cavity or organ, usually to withdraw fluid. These distinctions reinforce the specific purpose of "-meter" as a measurement tool within the medical field.