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: Physiology
a-receptor of estrogens are? 
Select and explain. 
A. Membrane receptors in breast, B. Nuclear receptors in breast, C. Membrane receptors in ovaries, D. Nuclear receptors in ovaries
B: Nuclear receptors in breast
Answer: B: Nuclear receptors in breast 
Explanation: Ans. is 'b' i.e., Nuclear receptors in breast(Ref: Principles of medical physiologlt p. 777).Estrogen binds to nuclear receptors --> Estrogen receptors (ERs)