Final answer:
The correct answer is C) PA catheter.
Step-by-step explanation:
The correct answer is C) PA catheter.
A PA catheter, also known as a pulmonary artery catheter, is a type of invasive monitoring device that provides direct information on cardiac output. It is inserted into the pulmonary artery to measure various hemodynamic parameters, including cardiac output, pulmonary artery pressure, and pulmonary artery wedge pressure.
Other options in the question, such as pulse oximeter, EKG, and invasive arterial pressure, do not directly measure cardiac output.