**Core Concept**
During embryological development, the gut undergoes a complex process of rotation and fixation. This process involves the caecum initially being placed near the stomach and then rotating to its final position near the junction of the small and large intestines. However, variations in this process can lead to abnormalities in the position of the caecum.

**Why the Correct Answer is Right**
In this scenario, the caecum is found to be placed below the stomach and in the midline. This suggests that during the rotation of the gut, there was a failure of the caecum to complete its normal rotation, resulting in a **persistent mesentery**. This means that the caecum remains attached to the back of the abdominal wall by a broad mesentery, leading to its midline position.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a non-rotation of the gut would result in a midgut volvulus, not a persistent mesentery.

**Option B:** This option is incorrect because a reverse rotation of the gut would result in a caecum located near the spleen, not in the midline.

**Option C:** This option is incorrect because an incomplete rotation of the gut would result in a caecum located near the stomach, but not necessarily in the midline.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the position of the caecum can be affected by various abnormalities during embryological development, and identifying these abnormalities is crucial for diagnosing and managing related conditions.

**Correct Answer: C. Incomplete rotation of the gut.**