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: Pharmacology
Ingestion of which of the following drug during pregnancy increase the risk of vaginal adenocarcinoma in a female offspring? 
Select and explain. 
A. Chlorpropamide, B. Progesterone, C. Diethyl stilbestrol, D. Chloramphenacol
C: Diethyl stilbestrol
Answer: C: Diethyl stilbestrol 
Explanation: Ingestion of diethylstibestrol during pregnancy increase the risk of vaginal adenocarcinoma in female offspring after maturity. It is also associated with an increase in functional abnormalities of the reproductive tracts in both male and female offsprings.