**Core Concept**
Extra amniotic second-trimester termination of pregnancy involves the injection of a substance into the space between the amniotic sac and the uterine wall to induce labor and expel the fetus. This procedure is often used in medicolegal terminations, where the pregnancy is terminated for reasons related to the law or ethics.

**Why the Correct Answer is Right**
Ethacrydine lactate is a substance used in extra amniotic second-trimester termination of pregnancy. It works by causing uterine contractions, which help to expel the fetus. Ethacrydine lactate is a quaternary ammonium compound that has a direct effect on the smooth muscle of the uterus, causing it to contract. This is achieved through the inhibition of the enzyme Na+/K+-ATPase, which leads to an increase in intracellular calcium and the subsequent contraction of the uterine muscle.

**Why Each Wrong Option is Incorrect**
**Option A:** Ethacrydine lactate is not used in this procedure, which makes this option incorrect. Ethacrydine lactate is actually used in other medical procedures, such as treating glaucoma.

**Option B:** Prostaglandins are not used in extra amniotic second-trimester termination of pregnancy. Prostaglandins are used in other termination procedures, such as medical abortion, where they cause the cervix to dilate and the uterus to contract.

**Option C:** Hypertonic saline is not used in extra amniotic second-trimester termination of pregnancy. Hypertonic saline is used in other termination procedures, such as saline infusion abortion, where it causes uterine contractions and fetal demise.

**Option D:** Glucose is not used in extra amniotic second-trimester termination of pregnancy. Glucose is not a substance that would be used to induce uterine contractions or terminate a pregnancy.

**Clinical Pearl / High-Yield Fact**
When performing a medicolegal termination of pregnancy, it is essential to use the correct substance to avoid complications and ensure a safe outcome for the patient. Ethacrydine lactate is a specific substance that should be used in extra amniotic second-trimester termination of pregnancy.

**Correct Answer:** A. Ethacrydine lactate