Final answer:
A. True. The claim regarding the WAN domain is true; corporations lease access from carrier networks. The idea that high-voltage wires are insulated is false; they are not because air acts as an insulator.
Step-by-step explanation:
The statement that the WAN domain of an IT infrastructure includes networks owned by a telco or a carrier network company that leases access to corporations is true. The Wide Area Network (WAN) is a telecommunications network that extends over a large geographical area for the purpose of computer networking. Corporations often lease access from these network companies to connect different parts of their businesses spread across countries or continents.
To address the second part of the question, the statement that high-voltage wires are wrapped in an insulating material is false. These wires are typically not covered in insulating materials because they are suspended high above the ground, where the risk of unintended contact is minimal, and the surrounding air provides sufficient insulation.
Finally, touching on the concept of refraction, the statement that refraction is useful in fiber optic cables for transmitting signals is true. Refraction is the bending of light as it passes from one material to another, which is a principle that allows fiber optic cables to transmit data over long distances with minimal loss. Refraction is a key principle enabling data transmission in fiber optic cables and thus is true.