This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
Which of the following explanations is not an explanation for decreased variability of the fetal hea tracing : 
Select and explain. 
A. Fetal "sleep state", B. Prematurity, C. Barbiturate ingestion, D. Fetal stimulation
D: Fetal stimulation
Answer: D: Fetal stimulation 
Explanation: Fetal stimulation