Explanation: The "T" in 10Base-T and 100Base-TX stands for **Twisted Pair** cabling. CAT-5 (Category 5) cable is the standard for these Ethernet systems. Its design utilizes twisted pairs of copper wires to minimize electromagnetic interference (EMI) and crosstalk between signals, ensuring robust data transmission – a fundamental principle in radio communications to maintain signal integrity. While 10Base-T technically uses two twisted pairs, 100Base-TX systems utilize all four twisted pairs within a CAT-5 cable for full-duplex operation and higher data rates. Therefore, CAT-5 cable with 4 twisted pairs is the universal and correct choice for these standards. Coaxial cable was used for older Ethernet standards (10Base-2/5, "Thinnet" and "Thicknet"), not the "T" series. Fiber optic cables are used for different Ethernet standards (e.g., 100Base-FX), which transmit light signals instead of electrical signals over copper.