**Core Concept**
The size of the uterus is an essential aspect of obstetrics and gynecology, particularly during pregnancy and in the assessment of uterine abnormalities. The normal size of the uterus can be estimated using various measurements, including its length, width, and depth.

**Why the Correct Answer is Right**
The correct answer is based on the average dimensions of a non-pregnant uterus. The uterus is a muscular, hollow, and pear-shaped organ that varies in size throughout a woman's life. In a non-pregnant woman, the uterus is approximately 7.5 cm (3 inches) in length, 4.5 cm (1.8 inches) in width, and 2.5 cm (1 inch) in depth. These measurements can be used as a reference to assess uterine size and detect abnormalities.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is too small for a normal non-pregnant uterus. A uterus smaller than 3 inches in length is typically considered abnormal.
**Option B:** This option is incorrect because it is too large for a normal non-pregnant uterus. A uterus larger than 3.5 inches in length is typically considered abnormal.
**Option C:** This option is incorrect because it is not a standard measurement for the size of the uterus.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that the size of the uterus can vary significantly during pregnancy, and the normal size of the uterus can be influenced by factors such as age, parity, and body habitus. A thorough gynecological examination and imaging studies, such as ultrasound, can help assess uterine size and detect abnormalities.

**Correct Answer:** C. 3 inches.