Answer: A. Regenerated fiber.
Step-by-step explanation:
When fibers are produced either by plants or animals, they're referred to as natural fibers. Cotton fibers and animal based fiber are both natural fibers.
Regenerated fiber is a manufactured fiber which is gotten when the cellulose of a plant is dissolved in chemicals after which the viscose method is being used to make it into a fiber again.
Therefore, the answer is A. Regenerated fiber.