Answer:
. 2C- acetyl Co-A from the link reaction  enters the kreb Cycle to combine with 4 Carbon Oxaloacetate to form 6-  Citrate
The Citrate forms intermediate Isocitrate, which eventually formed  6-C alpha ketoglutarate.
The alpha-ketoglutarate forms the intermediate succinyl-Co A, which later formed  5C-succinate.
5C -Succinate  forms 4C-fumarate, the latter formed 4C-malate- which eventually formed 4C-oxaloacetate.
The 4C of these compounds is fixed, to ensure constant availability of 4C of oxaloacatate for 2C Acetyl -CoA to bind it for the cycle to continuously occur for production of first product Citric Acid  from which other products are  formed from.
Explanation:
