**Core Concept**
The question is testing the understanding of the relationship between gestational age and uterine size in different types of abortions. This concept is crucial in obstetrics and gynecology, as it helps in determining the appropriate gestational age for various medical and surgical interventions.

**Why the Correct Answer is Right**
In a **missed abortion**, the gestational age corresponds to the uterine size because the embryo has not developed beyond a certain stage, and the uterus has not enlarged significantly. This type of abortion occurs when the embryo dies in the first trimester, but the body does not expel it. The uterine size remains consistent with the gestational age, as there is no significant growth or development of the embryo. The missed abortion is often diagnosed through ultrasound, which shows a gestational sac without an embryo or a fetus that has stopped growing.

**Why Each Wrong Option is Incorrect**
* **Option A:** Threatened abortion is not the correct answer because, in threatened abortion, the embryo is still viable, and the uterus is still enlarged due to the pregnancy. The gestational age does not correspond to the uterine size in this case.
* **Option B:** Incomplete abortion is not the correct answer because, in incomplete abortion, the embryo has partially been expelled from the uterus, and the uterine size is smaller than expected for the gestational age.
* **Option C:** Incomplete abortion is not the correct answer because, in inevitable abortion, the embryo has been completely expelled from the uterus, and the uterine size is significantly smaller than expected for the gestational age.

**Clinical Pearl / High-Yield Fact**
A missed abortion is a type of abortion where the embryo has died, but the body has not expelled it. It is essential to diagnose a missed abortion promptly, as it can lead to complications such as infection, hemorrhage, and uterine rupture.

**Correct Answer: C. Inevitable abortion**