What fibers are derived from the Angora goat and known for their silky feel and luster?

The correct answer is mohair fibers, which are sourced from the Angora goat. Mohair is celebrated for its distinctive silky feel and natural luster, making it a luxurious fiber often used in high-quality textiles and garments. The unique properties of mohair come from its smooth, long fibers that have a natural sheen, giving it an elegant appearance.

In contrast, cotton fibers are derived from the cotton plant and do not possess the same silky qualities or luster. Alpaca fleece comes from the alpaca animal and is known for its softness and warmth but lacks the specific sheen and smoothness attributed to mohair. Cashmere fibers, which come from cashmere goats, are also luxurious and soft, but they are distinct from mohair and do not exhibit the same level of luster. Hence, mohair is the correct choice as it directly relates to the Angora goat's fibers characterized by their silky texture and brilliance.