**Core Concept**
The question is testing the student's knowledge of the placental circulation and the arrangement of the umbilical vessels. The placenta is a complex organ that plays a crucial role in fetal development, and its vascular structure is essential for understanding various placental disorders.

**Why the Correct Answer is Right**
The umbilical vessels, which include two arteries and one vein, enter the placenta and branch out to supply the fetal tissues. In a normal placenta, the two umbilical arteries are closer together and are separated from the single umbilical vein by a thin layer of connective tissue. This arrangement is known as the **velamentous insertion**, where the vessels are separated before reaching the margin of the placenta. This is a common variant of placental insertion and is not associated with any adverse fetal outcomes.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the correct type of placental insertion. The question is asking about the arrangement of the umbilical vessels, not the type of placental insertion.
**Option B:** This option is incorrect because it does not describe the correct arrangement of the umbilical vessels. In a normal placenta, the two umbilical arteries are closer together, not separated by a broad base.
**Option C:** This option is incorrect because it does not describe the correct arrangement of the umbilical vessels. Velamentous insertion is a common variant of placental insertion, but it is not the correct answer to this question.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that velamentous insertion of the umbilical vessels is a normal variant and is not associated with any adverse fetal outcomes. However, it can be a risk factor for fetal distress if it is associated with other placental abnormalities.

**Correct Answer:** C.