**Core Concept**
The **supportive structures of the uterus** play a crucial role in maintaining its position and function. These include various **ligaments**, **muscles**, and **fascial layers**. The primary supportive structures are the **cardinal ligaments**, **uterosacral ligaments**, and the **levator ani muscle**.

**Why the Correct Answer is Right**
Given the options are missing, a general explanation is provided. Normally, the correct answer would be a structure not directly involved in uterine support, such as a blood vessel or a non-supportive ligament. The **cardinal ligaments** and **uterosacral ligaments** are key in providing lateral and apical support to the uterus, respectively. The **levator ani muscle** contributes to the pelvic floor's supportive mechanism.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option, it's challenging to provide a direct explanation. However, typically, an incorrect option might be a structure that does contribute to uterine support.
**Option B:** Similarly, without the option, it's hard to comment, but it could be another supportive structure.
**Option C:** Again, lacking the specific option, but it might be a ligament or muscle involved in uterine support.
**Option D:** This option could potentially be the correct answer if it represents a structure not involved in direct uterine support.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the **pelvic floor muscles**, particularly the **levator ani**, play a significant role in supporting the uterus and other pelvic organs. Damage to these muscles, such as during childbirth, can lead to **pelvic organ prolapse**.

**Correct Answer:** Correct Answer: D. Round ligament of uterus is actually a suspensory ligament.