Identify the First Step of the Citric Acid Cycle

Identify the first step of the citric acid cycle.

A) Citrate is converted to isocitrate.
B) Conjugate addition of water to the double bond of fumarate forms (S) -malate.
C) Acetyl-CoA reacts with oxaloacetate to form citrate.
D) FAD oxidizes succinate to fumarate.
E) The secondary alcohol of isocitrate is oxidized to a ketone by NAD⁺ and the ketone loses CO₂.