This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemistry of Lipids, Subject name: Biochemistry
Which of the following is a phytosterol? 
Select and explain. 
A. Sitosterol, B. Cholesterol, C. Ergosterol, D. Calcitriol
A: Sitosterol
Answer: A: Sitosterol 
Explanation: Sterols are molecules with the cyclopentano-perhydro-phenanthrene (CPP) nucleus Sitosterol Plant (phyto) sterol Ergosterol Fungal (myco) sterol Cholesterol Animal (zoo) sterol Plant sterols (sitosterol) | absorption of cholesterol Sitosterolemia Autosomal recessive disorder Defects in either ABCG5 or ABCG8 | Plant sterol levels Xanthomas Atherosclerosis