Final answer:
The most suitable gas mixture for calibrating exhaled gas analyzers is room air and carbon dioxide because it replicates the composition of the gases found in atmospheric air.
Step-by-step explanation:
The most appropriate gas mixtures for calibrating analyzers used for exhaled gas analysis during exercise would include a replica of the gases found in atmospheric air because these analyzers are designed to measure the levels of gases such as oxygen and carbon dioxide that are exhaled. Among the options, room air and carbon dioxide (option b) is the most similar to the composition of atmospheric air, which is primarily nitrogen and oxygen with small amounts of carbon dioxide and other gases. This mixture would allow for calibration of the analyzer under conditions that are close to natural respiration.