Each of the Following Was Used to Elucidate the TCA

Each of the following was used to elucidate the TCA cycle EXCEPT

A) using radiolabeled acetate to determine which carbons were oxidized to CO2 .
B) the use of crude enzyme preparations from a variety of sources such as cucumber seeds and beef liver.
C) adding a variety of short-chain fatty acids commonly found in cells to detect activity.
D) the use of C14-labeled carbon compounds as a source of carbon under anoxic conditions.
E) using C13 to determine which intermediates are enriched under various growth conditions.