Isocitrate dehydrogenase has all of the characteristics EXCEPT:

A) ADP raises the K_m for isocitrate by a factor of 10.
B) virtually inactive in the absence of ADP.
C) sufficiently exergonic to pull the aconitase reaction forward.
D) allosterically inhibited by NADH and ATP.
E) an oxidative-decarboxylation reaction.