system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
True statement(s) out of the following is/are: a) β1  receptors in heart stimulate its contractions b) β2 receptors in heart stimulate its contractions c) β2 receptors are present in smooth muscles d) α1 receptors cause preganglionic stimulation e) α2  receptors cause postganglionic feedback inhibition
assistant
The correct answer is  None