Final answer:
Ascorbic acid is used as a reducing agent in the radiochromium labeling process.
option d.
Step-by-step explanation:
In the radiochromium labeling process, ascorbic acid is used as a reducing agent. A reducing agent is a substance that causes another substance to gain electrons, which results in a decrease in its oxidation state. Ascorbic acid reacts with the oxidized form of chromium to convert it to its reduced form, allowing it to be used as a radiotracer.
option d.
Learn more about radiochromium labeling process