Sequence of organic acids in Krebs cycle is
A. Citric acid `rarr` oxalosuccinic acid `rarr` isocitric acid
B. Citric acid `rarr` isocitric acid `rarr` oxalosuccinic acid
C. Isocitric acid `rarr` oxalosuccinic acid `rarr` citric acid
D. Oxalosuccinic acid `rarr` isocitric acid `rarr` citric acid