Match the cofactors below with their roles in the pyruvate dehydrogenase complex reaction.

Cofactors:
A. Coenzyme A (CoA-SH)
B. NAD+
C. Thiamine pyrophosphate (TPP)
D. FAD
E. Lipoic acid in oxidized form

Roles:
Attacks and attaches to the central carbon in pyruvate.
Oxidizes FADH2.
Accepts the acetyl group from reduced lipoic acid.
Oxidizes the reduced form of lipoic acid.
Initial electron acceptor in oxidation of pyruvate.

The characteristics of two different types of reactions are shown below: reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of an element. which statement is true about the atoms of the elements that participate in the two reactions? their identity changes in both reaction a and reaction b. their identity changes in reaction a but not in reaction b. their identity changes in reaction b but not in reaction a. their identity remains the same in both reaction a and reaction b.