**Core Concept**
The question is testing the knowledge of the highest mortality rate associated with pregnancy. Pregnancy-related mortality is a significant concern worldwide, and understanding the risks involved is crucial for obstetricians and healthcare providers.

**Why the Correct Answer is Right**
The highest mortality rate in pregnancy is typically associated with **Eclampsia**, a severe complication of preeclampsia characterized by seizures in a pregnant woman. Eclampsia is often related to **placental abruption**, which occurs when the placenta separates from the uterus, leading to **hypoxia** and **coagulopathy**. The pathophysiology involves **endothelial dysfunction**, leading to increased vascular resistance and **thrombocytopenia**.

**Why Each Wrong Option is Incorrect**
* **Option A:** Amniotic fluid embolism is a severe condition, but it is not the highest mortality rate in pregnancy.
* **Option B:** Hemorrhage is a significant cause of maternal mortality, but it is not the highest mortality rate in pregnancy.
* **Option C:** Cardiac disease is a leading cause of maternal mortality in developed countries, but it is not the highest mortality rate in pregnancy.

**Clinical Pearl / High-Yield Fact**
Remember that the **"TRAP"** mnemonic can help you remember the highest mortality rates in pregnancy: **T**ubal pregnancy (ectopic pregnancy), **R**hesus incompatibility, and **A**mniotic fluid embolism.

**Correct Answer:** C. Hemorrhage