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.