Step 1: Understanding the question.
The question is asking about the hormone released during the foetal ejection reflex in humans and its origin.
Step 2: Historical context.
During childbirth, the foetal ejection reflex is a mechanism in which oxytocin is released from the maternal pituitary to induce uterine contractions and aid in the delivery of the baby.
Step 3: Analysis of the options.
- (A) oxytocin, foetal pituitary: Incorrect. Oxytocin is released from the maternal pituitary, not the foetal pituitary.
- (B) oxytocin, maternal pituitary: Correct. Oxytocin is released from the maternal pituitary during the foetal ejection reflex.
- (C) human chorionic gonadotropin, placenta: Incorrect. Human chorionic gonadotropin is produced by the placenta during early pregnancy, but it is not involved in the foetal ejection reflex.
- (D) progesterone, corpus luteum: Incorrect. Progesterone is involved in maintaining pregnancy, but it does not trigger the foetal ejection reflex.
Step 4: Conclusion.
The correct answer is (B) oxytocin, maternal pituitary, as this is the hormone and source involved in the foetal ejection reflex.
Final Answer: oxytocin, maternal pituitary.