During aerobic respiration, in which of the following steps does decarboxylation occur:

(a) 1,3 bisphosphoglyceric acid to 3-phosphoglyceric acid
(b) Pyruvic acid to ethanol
(c ) Pyruvic acid to Acetyl CoA
(d) $\alpha$ ketoglutaric acid to Succinyl CoA

During aerobic respiration, decarboxylation occurs during link reaction and Krebs cycle. Therefore, when pyruvic acid is converted to acetyl CoA carbon dioxide is released. Similarly, when $\alpha$ketoglutaric acid is converted to succinyl CoA ${\mathrm{CO}}_2$ is released.