When glucose is converted to pyruvate by glycolysis in the cytosol, the net result is that only two molecules of ATP are produced per glucose molecule, which is less than 10% of the total free energy potentially available from oxidizing the sugar. By contrast, about ____ molecules of ATP are produced when mitochondria are recruited to complete the oxidation of glucose that begins in glycolysis.
选项：

A:20
B:24
C:27
D:30