This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Parasitology Pa 1 (Protozoology), Subject name: Microbiology
All are seen in cyst of E. histolytica except - 
Select and explain. 
A. Glycogen mass, B. Chromatid bars, C. Eccentric nucleus, D. Ingested RBC
D: Ingested RBC
Answer: D: Ingested RBC 
Explanation: Ingested RBC are seen in trophozoite not in cyst. Option 1, 2, 3, 4 Cystic stage of E. histolytica: Size and shape - 12-15 um, spherical. Cyst wall - highly refractive membrane. Nucleus - Eccentric nucleus, mature cyst contain 4 nucleuses. Cytoplasm - 1-4 chromatid bodies, glycogen mass (stain brown with iodine), both gradually disappear as the cyst matures from uninucleate to quadrinucleate. Chromatoid body - Present in immature cysts, Thick bars with rounded ends. Image:Mature Cyst of Entamoeba coli in an unstained wet mount preparation. fig:-showing labelled diagram of trophozoite and cyst