Which of the following synthetic fibers is known for its elasticity?

Spandex is well-known for its exceptional elasticity, which is a key characteristic that sets it apart from other synthetic fibers. This fiber can stretch significantly and return to its original shape, providing not only comfort but also freedom of movement. This makes spandex a popular choice in garments that require a close fit and flexibility, such as activewear, swimsuits, and undergarments. Its ability to stretch up to five times its original length and maintain its shape is critical for applications where both fit and comfort are essential.

In contrast, other synthetic fibers, while they may offer certain advantages like durability or moisture-wicking properties, do not exhibit the same level of elasticity as spandex. For example, acrylic and polypropylene are primarily known for being lightweight and quick-drying, while olefin offers resistance to stains and moisture but does not provide the same stretchability. Ultimately, spandex's unique elastic properties are what make it the go-to option when flexibility and support in fabric are required.