Isotopic Labeling of a Specific Substrate Carbon with ¹³C,which Has

Isotopic labeling of a specific substrate carbon with ¹³C,which has an extra neutron,is particularly useful for investigating biochemical pathways because

A) the presence of the radioisotope greatly accelerates the pathway,which makes it easier to study.
B) the position of the labeled carbon can be traced through products of the pathway to characterize the pathway reactions.
C) the radioisotope blocks each pathway at a specific step.
D) the radioisotope readily exchanges neutrons so that all neighboring carbons become labeled and easier to detect with NMR.
E) radiolabels generally are easier to track in cells than fluorescent labels.