**Core Concept**
The question is testing the understanding of a genetic disorder affecting collagen synthesis, specifically the role of lysyl hydroxylase in stabilizing collagen fibers. Lysyl hydroxylase is an enzyme responsible for hydroxylating lysine residues in procollagen, allowing for the formation of stable collagen cross-links.

**Why the Correct Answer is Right**
The deficiency of lysyl hydroxylase leads to the accumulation of procollagen, which cannot form stable cross-links. This results in the production of abnormal collagen fibers that are fragile and prone to degradation. The skin and joints of affected individuals exhibit characteristics of a connective tissue disorder, such as extremely pliable skin, easy bruising, and joint hyperextensibility. The ultrastructural examination of a skin biopsy would likely reveal abnormalities associated with the collagen fibers, specifically the presence of abnormal, fragmented, or sparse collagen fibrils.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the question specifically mentions a deficiency of lysyl hydroxylase, which affects collagen synthesis, not elastin.
* **Option B:** This option is incorrect because the question is not related to the structure or function of the basement membrane.
* **Option C:** This option is incorrect because the question is not related to the structure or function of the cell membrane.

**Clinical Pearl / High-Yield Fact**
Lysyl hydroxylase deficiency is a rare genetic disorder that affects collagen synthesis, leading to characteristic skin and joint manifestations. It is essential to recognize the clinical presentation of this disorder and consider the underlying biochemical defect in patients with similar symptoms.

**Correct Answer:** D. collagen fibers