Introduction:
Pyruvic acid is a three-carbon compound that plays a crucial role in cellular respiration. It is the end product of glycolysis, a metabolic pathway that converts glucose into pyruvate. In aerobic conditions, pyruvic acid undergoes further oxidation in the mitochondria to produce carbon dioxide, water, and energy. This process is known as the Krebs cycle or the citric acid cycle.

Oxidation of Pyruvic Acid:
During the Krebs cycle, each pyruvic acid molecule is completely oxidized, resulting in the release of energy and the production of carbon dioxide. To understand the number of oxygen atoms required for the complete oxidation of pyruvic acid, we need to examine the chemical equation for this process.

The chemical equation for the oxidation of pyruvic acid is as follows:
Pyruvic Acid + NAD+ + CoA → Acetyl CoA + NADH + H+ + CO2

Analysis:
From the chemical equation, we can observe that one molecule of pyruvic acid reacts with one molecule of NAD+ and one molecule of CoA. This reaction results in the production of one molecule of Acetyl CoA, one molecule of NADH, one molecule of H+, and one molecule of CO2.

Since each molecule of CO2 contains one atom of carbon and two atoms of oxygen, the complete oxidation of one molecule of pyruvic acid requires two atoms of oxygen.

However, during glycolysis, one molecule of glucose is converted into two molecules of pyruvic acid. Therefore, if we consider the oxidation of one molecule of glucose, which produces two molecules of pyruvic acid, the total number of oxygen atoms required for complete oxidation would be four.

Conclusion:
In conclusion, the number of oxygen atoms required for the complete oxidation of pyruvic acid is four when considering the oxidation of one molecule of glucose. However, if we are specifically referring to the oxidation of one molecule of pyruvic acid, the number of oxygen atoms required is two. Therefore, the correct answer to the given question is option d) 0, as none of the provided options accurately represent the number of oxygen atoms required for the complete oxidation of pyruvic acid.

Option A is right ans..