**Core Concept**
The cause of fetal death in ectopic pregnancy is related to the inadequate development and maintenance of the placental circulation, leading to insufficient oxygen and nutrient supply to the embryo. This is due to the abnormal implantation of the embryo outside the uterine cavity.

**Why the Correct Answer is Right**
The correct answer is related to the concept of **histotrophic nutrition**, where the embryo initially receives nutrients from the surrounding maternal tissue, rather than relying on the placental circulation. However, this histotrophic nutrition is insufficient to support the growth and development of the embryo beyond a certain point. As the embryo grows, it requires a more efficient source of oxygen and nutrients, which cannot be provided by the histotrophic nutrition. This leads to the death of the embryo due to **ischemia** and **hypoxia**.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not directly relate to the cause of fetal death in ectopic pregnancy. While **fibrinolysis** may be involved in the pathophysiology of ectopic pregnancy, it is not the primary cause of fetal death.
* **Option B:** This option is incorrect as **tubal rupture** may occur in ectopic pregnancy, but it is not the direct cause of fetal death. Tubal rupture can lead to severe bleeding and shock, but it does not directly affect the embryo.
* **Option C:** This option is incorrect as **infection** may be a complication of ectopic pregnancy, but it is not the primary cause of fetal death. Infection can lead to sepsis and shock, but it does not directly affect the embryo.

**Clinical Pearl / High-Yield Fact**
In ectopic pregnancy, the embryo is often smaller than expected due to the inadequate development and maintenance of the placental circulation. This can make it more difficult to diagnose ectopic pregnancy, especially in the early stages.

**Correct Answer: C. Ischemia and hypoxia due to inadequate histotrophic nutrition.**