Instructions: In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Input: Question: Thiamine pyrophosphate (PPT) is not coenzyme of:
Options: <1> Pyruvate dehydrogenase (synthesis of acetyl CoA). <2> Alpha-ketoglutarate dehydrogenase (citric acid cycle). <3> Transketolase (pentose phosphate pathway). <4> Transaldolase (pentose phosphate route). <5> Pyruvate decarboxylase (ethanolic fermentation).
Output:
4