**Core Concept**
Hyalinisation of the periodontal ligament (PDL) is a pathological change that occurs due to excessive mechanical stress, leading to the deposition of homogenous, eosinophilic material within the PDL space. This process disrupts the normal architecture and function of the PDL, potentially causing tooth mobility and other periodontal complications.

**Why the Correct Answer is Right**
Hyalinisation of the PDL is a consequence of chronic overloading, which triggers a series of cellular and molecular responses. The excessive mechanical stress causes the death of periodontal ligament cells (fibroblasts), leading to the release of inflammatory mediators and the activation of fibroblasts, which then produce an excessive amount of collagen. However, the newly synthesized collagen is not properly organized, resulting in the formation of homogenous, hyaline-like material within the PDL space. This process is similar to the one observed in scurvy, where the lack of vitamin C impairs collagen synthesis and deposition.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the histopathological changes associated with hyalinisation of the PDL.
**Option B:** This option is incorrect because it is a consequence of different pathological process, specifically the loss of periodontal ligament cells due to infection or inflammation.
**Option C:** This option is incorrect because it is a characteristic of scurvy, a disease caused by vitamin C deficiency, rather than hyalinisation of the PDL.

**Clinical Pearl / High-Yield Fact**
To avoid hyalinisation of the PDL, orthodontic forces should be kept within the recommended limits, and the application of forces should be gradual and continuous. This can be achieved by using a force magnitude of 1-2 N per tooth and applying forces for a duration of 10-15 minutes.

**Correct Answer: D.**