Correct Answer: A

Rationale: The correct answer is A: 'Stimulates milk ejection.' Oxytocin is responsible for contracting the muscles around the milk ducts, pushing milk into the nipples for breastfeeding. This process is known as milk ejection or let-down. The other choices are incorrect because oxytocin's primary function is to facilitate milk ejection rather than directly stimulating the production of milk, the development of lactoferrin, or the secretion of relaxin.

Correct Answer: D

Rationale: Human chorionic gonadotropin (hCG) is the hormone detected in pregnancy tests. During pregnancy, the placenta produces hCG, which can be detected in the urine or blood to confirm pregnancy. Estrogen and progesterone are also essential hormones in pregnancy but are not typically used for pregnancy tests. Luteinizing hormone (LH) is involved in the menstrual cycle and ovulation, not pregnancy.

Correct Answer: B

Rationale: Inevitable abortion is characterized by an open os. This condition is associated with heavy bleeding. While severe cramping can be present in inevitable abortion, the key characteristic is the open os, making choice B the correct answer. Choices A and D are incorrect because they do not specifically describe the defining feature of inevitable abortion, which is the open os.

Correct Answer: D

Rationale: Septic abortion is characterized by maternal pyrexia. Maternal pyrexia, or fever, is a hallmark sign of septic abortion due to infection. Backache and heavy bleeding can be present in abortion but are not specific to septic abortion. 'Os open' does not directly characterize septic abortion.

Correct Answer: D

Rationale: Sterilization is considered the most effective method of contraception because it permanently prevents pregnancy. Barrier methods, hormonal pills, and IUDs are highly effective as well, but they are reversible methods and may have a higher failure rate compared to sterilization.